If weight loss is your goal, you’re probably familiar with the low carb diet.
In fact, you may be using some form of this diet plan right now or are maybe thinking about trying it out to see if it lives up to the hype.
In either case, you’re going to want to stop and read this article, because I’m going to reveal the “secrets” behind the low carb diet and how it really works.
Does The Low Carb Diet Work?
Let’s start with the first question you probably have: does the low carb diet actually work for weight loss?
The answer is YES.
Absolutely, positively, without question, no doubt about it. This type of diet plan can work.
This is a fact that has been confirmed numerous times in studies as well as in the real world by the countless people who have used it successfully.
So yes, the low carb diet is 100% capable of making weight loss happen.
But, Here’s The Thing…
Now for the fun part.
You see, whether or not the low carb diet works isn’t really the question we need to be asking here.
Because, honestly, all kinds of diets can “work.”
Low calorie, low fat, low carb, keto, Paleo, gluten-free, vegan, vegetarian, intermittent fasting, clean eating, Weight Watchers, The Zone, Mediterranean, South Beach, and on and on and on.
There is a seemingly never-ending list of weight loss diets that are capable of “working.” In fact, virtually every single diet in existence – no matter how weird, crazy, dangerous, or stupid it is – has plenty of people who have successfully lost weight while using it.
So, the fact that the low carb diet “works” isn’t really all that special or important.
What IS important, however, is why it works, how it works, and whether eating low carb is even remotely necessary at all for someone who wants to lose weight.
Because, when you start to truthfully answer these questions, you quickly realize that:
- The low carb diet is not at all what it seems to be.
- The biggest proponents of it are either wrong or lying to you.
- The effectiveness of low carb diets has nothing to do with carbs.
Don’t believe me? I’ll prove it.
Yes, the low carb diet can (and does) work for weight loss. But then again, the same is true of virtually every diet known to man. What’s really important here is why it works, how it works, and whether the “low carb” aspect of it is responsible for its effectiveness. As you’re about to see, it’s not.
The Truth About Weight Loss: It Has Nothing To Do With Carbs
(Note To The Low Carb Dieters Who Are Reading This: This next section will contain an “argument” you’ve probably heard before, and I know you’re going to disagree with it. That’s fine. All I ask is that you please stick with me anyway, because the sections that come after it are going to contain the things you need to hear. If it helps, you’re more than welcome to curse me and call me names while reading this section. Deal? Awesome.)
Weight loss and weight gain (or really, fat loss and fat gain) come down to calories in vs calories out.
Here’s the really short version of how it works…
- Caloric Surplus
If you consistently eat more calories than your body burns, you end up in a “caloric surplus.” Because you took in more calories than your body needed to use for energy, the leftover calories that weren’t burned got stored in your body for later use, primarily in the form of body fat. This, right here, is the only scenario in which fat is ever gained.
- Caloric Deficit
If you consistently eat fewer calories than your body needs to burn for energy, you end up in a “caloric deficit.” Because you took in fewer calories than your body needed, your body was forced to dip into the backup fuel source that it has previously stored in itself for this very purpose – your body fat – and burn that instead. This, right here, is the only scenario in which fat is ever lost.
(For additional details, check out How To Lose Fat and How Many Calories Should I Eat A Day To Lose Weight)
Which is all to say that in order for ANY weight loss diet to EVER work, it HAS to involve eating fewer calories so that a caloric deficit is consistently present.
When this happens, the diet works.
When it doesn’t, the diet fails.
This is ALWAYS true… 100% of the time… regardless of what kind of diet it is.
A caloric deficit is the sole cause of fat loss and the sole requirement of an effective weight loss diet.
With me so far? Cool.
What About Carbs?
We’ve now reached the point where you’re probably realizing that low carb diets work (hell, I even said so myself), yet they have nothing to do with calories.
No counting calories. No eating fewer calories. And certainly no caloric deficits.
Instead, low carb diets are all about carbs.
That’s the REAL “thing” you need to eat less of in order to lose weight… or so the proponents of this diet will claim. Not calories.
In fact, as long as you eat low carb, you can supposedly eat as many calories as you want and still lose weight just fine.
Why? Because this whole “calorie thing” is supposedly just a stupid, flawed, outdated myth/lie/scam, and carbs are the true determining factor of weight loss and weight gain.
After all, I said at the beginning of this article that low carb diets definitely DO work for weight loss. I stated this as a fact that has been confirmed in studies as well as in the real world… countless times over.
Therefore, what I’m saying about calories has to be false, right?
Well, let’s see about that…
A caloric deficit is the sole cause and requirement of fat loss. “Calories in vs calories out” is indeed the primary determining factor of weight loss and weight gain. Low carb diets dispute this and claim it is in fact carbs – not calories – that are the real key.
The 7 Real Reasons Why Low Carb Diets Work
It’s time to reveal the big secrets behind how the low carb diet really works for weight loss.
It’s primarily a combination of 7 evidence-based reasons…
Reason #1: You Lose Water Weight
The carbs we eat are stored as glycogen in our muscles and liver. For every gram of glycogen being stored, about 3 grams of water are stored along with it (source).
This is why people who start a low carb diet almost immediately lose a few pounds.
Many of these people will think “Wow, low carb really does work! It’s only been a week and I’ve already lost a bunch of fat!”
Only, they didn’t.
What they lost is some meaningless water weight, all of which would be gained right back as soon as they start eating more carbs.
(Side Note: This is also the biggest reason why people who overeat one day will often wake up the next day and see that they’ve gained a few pounds overnight. They’ll then proceed to freak out thinking it’s body fat when it’s largely just water retention caused by the extra carbs they consumed. A few days back to their usual calorie/carb intake will make that water retention subside. Additional details here: The 12 Causes Of Unexplained Weight Gain)
Now, am I saying that ALL of the weight people lose while on a low carb diet is just water weight, not fat?
I’m just pointing out that most (if not all) of the weight people lose during their initial week or so is indeed just water.
But, I will gladly admit that after this initial period, the weight being lost is body fat. Let’s take a look at the real reasons for how and why it happens…
Most, if not all, of the initial weight loss seen during the first 1-2 weeks on a low carb diet plan is due to a loss of water weight, not body fat.
Reason #2: Eating More Protein Keeps You Fuller
In addition to eating fewer carbs, low carb diets also involve eating more protein.
Sometimes this occurs directly, where the diet will literally say “eat more protein” or “eat this much protein” or “eat the foods on this special list” (and the list contains high protein foods), or something similar.
Other times, it occurs a bit more indirectly, simply as a result of the fact that if you greatly restrict an entire macronutrient (in this case, carbs) from a person’s diet, they’re going to kinda have to start eating a lot more of something else (protein and fat) to compensate and… you know… not starve to death.
Sometimes it’s a combination of both.
For this reason, low carb diets can more accurately be described as being low carb, higher protein diets.
Why am I pointing this out, you ask?
Because protein is the macronutrient playing the largest role in controlling hunger.
Now guess what happens when you start eating more of something that helps you stay fuller, longer?
That’s right… you end up eating fewer total calories because you’re not as hungry.
And when fewer total calories are eaten, you become more likely to end up being in a caloric deficit.
And when a caloric deficit exists, fat loss happens because it’s calories – NOT carbs – that dictate fat loss and fat gain.
But wait… there’s more!
Low carb diets always involve eating significantly more protein, and protein plays a major beneficial role in hunger control. This indirectly leads to fewer calories being eaten (because people naturally eat less when they aren’t as hungry), which increases the potential for a caloric deficit to exist.
Reason #3: Eating More Protein Increases Metabolic Rate
In addition to protein’s hunger-controlling qualities, it’s also the macronutrient that has the largest thermic effect.
This means it will cause a person’s Thermic Effect of Food (TEF) to increase the most, which is defined as the calories your body burns digesting, absorbing, and metabolizing the foods you eat.
Basically, the higher your TEF is, the more calories your body naturally burns each day. With carbs, TEF is about 5-10%. With fat, it’s about 0-3%. But with protein, TEF is 20-30%. [source]
So, for example, if a food contains 100 calories from protein, 20-30 of those calories will be burned to process that food. With fat or carbs, you would likely only burn 0-10 calories.
Why am I pointing this out, you ask?
Because not only will a higher protein intake lead to fewer total calories being eaten each day thanks to its hunger-controlling benefits, but it will also lead to more calories being burned each day… which is yet another factor (TEF accounts for about 10% of a person’s overall metabolic rate) that contributes to the presence of a caloric deficit (sources: here, here, here, and here).
But wait, there’s even more!
Since protein has a much higher thermic effect than other macronutrients, and since low carb diets involve eating more protein, a person on this type of diet plan will often end up with an higher metabolic rate due to their higher protein intake, thus increasing the potential for a caloric deficit to exist.
Reason #4: Eating More Protein Preserves Muscle
As if hunger control and increased TEF weren’t enough, here’s another fun fact about protein: it’s the dietary factor playing the largest role in preventing muscle loss while in a caloric deficit (sources: here, here, here, here, here, here, and here).
Why am I pointing this out, you ask?
Because a higher protein intake during a period of weight loss will ensure that more of the weight being lost is body fat rather than lean muscle mass. This, in turn, will help to keep a person’s metabolic rate comparatively higher as they lose weight because the body burns more calories maintaining muscle than it does maintaining fat.
- One pound of fat burns about 2 calories per day at rest.
- One pound of muscle burns about 6 calories per day at rest.
Which means, the more muscle you have, the more calories your body will naturally burn each day (both at rest and during activity)… which is yet another factor that contributes to the presence of a caloric deficit.
A higher protein intake helps to preserve muscle tissue while body fat is lost. And since muscle is three times more metabolically active than fat, a person’s metabolic rate will stay some degree higher during a period of fat loss, thus increasing the potential for a caloric deficit to exist.
Reason #5: Eating More Vegetables And Fiber Keeps You Fuller
Just like with protein, low carb diets also directly or indirectly involve an increase in vegetable consumption, which leads to an increase in fiber intake.
Again, this either happens because the diet specifically says to eat more vegetables and/or a certain amount of fiber, or because vegetables appear near the very top of a low carb diet’s list of “low carb foods you’re allowed to eat.” Or both.
Why am I pointing this out, you ask?
It provides “bulk” within your stomach, which increases how physically full your stomach is (which, in turn, increases how physically full you feel). Fiber also helps to slow the digestion of the foods and meals we eat, which increases how long we stay full after eating them.
In addition to being an excellent source of fiber, vegetables also happen to be relatively high in water content, which is yet another nutritional quality known for promoting fullness (sources: here, here, here, here, and here).
Which is all to say that when you eat more vegetables/fiber, you’re going to get a meaningful amount of hunger-controlling benefits.
And guess what happens when you start getting these hunger-controlling benefits? That’s right… you end up eating fewer total calories because you’re less hungry.
Low carb diets typically involve eating more vegetables/fiber, which plays a major role in hunger control. Just like with protein, this indirectly leads to fewer calories being eaten (because people naturally eat less when they aren’t as hungry), which increases the potential for a caloric deficit to exist.
Reason #6: Eating More Fat Keeps You Fuller
Low carb diets also directly or indirectly involve eating more fat.
Why am I pointing this out, you ask?
Because, like protein and fiber, fat is another nutrient playing a beneficial role in hunger control thanks to its ability to slow the digestion of a food/meal and the absorption of glucose into the blood stream (sources here and here)… which yet again leads to fewer total calories being eaten because you’re less hungry.
Low carb diets involve eating more dietary fat, which plays positive roles in hunger control. Just like with protein and fiber, this increases the potential for a caloric deficit to exist because people naturally eat fewer calories when they aren’t as hungry.
Reason #7: Eating Fewer Carbs = Eating Fewer Calories
It’s now time for the biggest reason why the low carb diet works. This is the most top secret secret of all the secrets.
Are you ready?
Low carb diets are built around one very obvious fundamental principle: eating fewer carbs.
Sometimes the diet is very low in carbs, sometimes it’s extremely low in carbs, and sometimes it’s a straight up “no carb” diet.
Why am I pointing out something so obvious, you ask?
Because carbs just so happen to be the macronutrient/food group that comprises the majority of a typical person’s diet. It also happens to be the macronutrient/food group that encompasses the majority of the foods that people tend to overeat the most.
You know… foods like:
- sugary foods
- snack foods
- junk foods
- sports drinks
- and on and on and on.
These are the kinds of foods that you’re not allowed to eat on a low carb diet.
Now guess what happens when you greatly restrict or completely eliminate all of these foods? Guess what happens when you remove a ton of carbs (which contain 4 calories per gram) from a person’s diet?
You end up removing a ton of calories, too.
And thus, fewer total calories end up being eaten.
And it’s this, above all else, that makes low carb diets “work.”
In fact, it’s this, above all else, that makes EVERY diet work. Let me explain…
Direct Deficit Diets vs Indirect Deficit Diets
In my book, Superior Fat Loss, I go into detail about what I like to call “direct deficit diets” and “indirect deficit diets.” Here’s the short version:
- Direct Deficit Diets
These are diets built around DIRECTLY creating your required caloric deficit, and then designing everything else with that as the foundation of your diet.
- Indirect Deficit Diets
These are diets built around placing any number of (often unnecessary) rules and restrictions on what, when, and how you can eat, thereby INDIRECTLY causing your required caloric deficit to exist (often while claiming calories have nothing to do with it).
The low carb diet is a perfect example of an indirect deficit diet.
When it works, it’s because a caloric deficit was indirectly created. The reduction in carb intake – in and of itself – had nothing to do with it.
That’s because weight loss always comes down to calories in vs calories out. Eating fewer carbs is just an indirect means to eating fewer calories.
The same can be said for eating less fat, or less sugar, or less grains, or less “dirty foods,” or less non-Paleo foods, or less “bad foods,” or fasting for significant portions of the day, or not eating after 7PM, or any other (unnecessary) dietary method that restricts what you can eat or the manner in which you can eat it.
That’s not to say this sort of stuff can’t work for losing weight. It certainly can. Like I said before, low carb diets DO work.
However, despite what the proponents of these methods might falsely claim or the users of these methods might falsely believe… it’s NEVER these other “restrictions” that are making weight loss happen. It’s always the underlying caloric deficit that they are indirectly causing.
Well, I should say… the underlying caloric deficit that they are hopefully causing.
The Problems With Indirect Deficit Diets Like Low Carb
With all else being equal (adherence, consistency, execution, etc.), direct deficit diets are guaranteed to work.
But indirect deficit diets like low carb? With all else being equal, many of them CAN work. And, like I’ve been saying since the beginning, many often DO work. No doubt about that at all.
The problem, however, is that it’s now less of a guarantee and more of a lucky side effect.
What I mean is, instead of directly doing the one thing that truly needs to be done for weight loss to occur (creating a caloric deficit), these diets ignore calories while placing various unnecessary rules and restrictions on the way that you eat (e.g. foods you can or can’t eat, times you can or can’t eat, etc.), thus indirectly causing you to eat less… thus indirectly causing a deficit to exist.
And that leads to two big problems…
- You’re doing stuff you don’t truly NEED to be doing for the purpose of causing the one and only thing you NEED to be doing… and these non-essential things are not always guaranteed to be enough to make it happen.
Meaning, regardless of the type of non-calorie-based rules and restrictions a diet employs, it’s always going to be possible for a person to out-eat them. So while greatly restricting or completely eliminating carbs should hypothetically make it harder for someone to eat too many calories, it certainly doesn’t make it impossible (i.e. removing the “bad” foods isn’t guaranteed to prevent a person from simply overeating “good” foods instead). Which, of course, is why so many of the people on these types of diets still fail to reach their weight loss goals despite following all of their unnecessary rules. Speaking of which…
- The various unnecessary and often excessive rules and restrictions these diets entail typically force you to eat in a manner that doesn’t suit your personal preferences (or just flat out annoys the crap out of you).
And doing things that go against your own personal preferences – like avoiding carbs even though you enjoy eating them and want to continue doing so (plus the added fun of the Ironic Process Theory: the more you try to avoid carbs, the more you’re going to obsess over them) – is the #1 way to create problems with diet adherence and long-term sustainability. This, probably even more so than the first problem, is why people on these types of diets either fail to lose weight in the first place, or fail to keep that weight off after losing it.
This is something I bring up for the people who say things like: “If the low carb diet can work, who cares why it works? Even if we know it’s just making us eat fewer calories? As long as it’s working, who really cares? Counting calories seems annoying anyway, so I’d rather just stop eating carbs because it seems simpler. So why not just do that?”
Well, these two potential problems would be my response to those questions.
When you eat fewer carbs, you eat fewer calories. Plain and simple. 1 gram of carbs contains 4 calories. It tends to be the macronutrient that comprises the majority of most people’s diets and the foods people are most likely to overeat. Therefore, when you greatly restrict or completely remove such a significant part of a person’s overall diet, you also end up removing a significant amount of calories. And when that happens, a caloric deficit becomes a lot more likely to (indirectly) exist.
“More Proof! I Want Even More Proof!”
What’s that you say?
All of the facts, logic, and evidence I’ve provided so far isn’t enough, and you want more?
Examples Of HIGH Carb Diets Working Well For Weight Loss
Here now is a handful of perfect real-world examples where people went on crazy/extreme diets that were very high in carbs and yet still lost weight just fine.
Why did these people go on these crazy diets, you ask?
In some (but not all) cases, they did it to help prove the very same points I’ve been making throughout this article, the most notable of which is that it’s calories and not carbs (or anything else) that determines fat loss and fat gain.
Here’s a breakdown of exactly what happened…
(Note: I am not recommending any of these diets. Like I said, they are all crazy, extreme, and obviously far from ideal. However, they’re still useful for showing how unnecessary a low carb diet is for losing weight.)
- The Twinkie Diet
Mark Haub, a professor of human nutrition at Kansas State University, went on a 10-week diet comprised largely of snack foods that are super high in carbs/sugar (e.g. Twinkies, Little Debbie cakes, Doritos, Oreos, brownies, sugary cereals, etc.). However, he also created a caloric deficit. Guess what happened? He lost 27 lbs in 2 months and reduced his body fat percentage from 33.4% to 24.9%. He also reduced his “bad” cholesterol (LDL) by 20%, increased his “good” cholesterol (HDL) 20%, and reduced triglycerides by 39%. (source)
- The Fast Food Diet
John Cisna, a high school science teacher from Iowa, went on a McDonald’s-only diet for 3 straight months comprised primarily of foods like Big Macs, Quarter Pounders, McMuffins, various desserts (such as sundaes and ice cream), and other typical fast food items. However, he also created a caloric deficit. Guess what happened? He lost 37 lbs during those 90 days. (source)
- The Potato Diet (Version 1)
Chris Voigt, the head of the Washington State Potato Commission (yup, apparently that’s a thing), went on a diet where he ate nothing but potatoes for 60 days. However, he also unintentionally created a caloric deficit (partially because he was so full from all of the fiber the potatoes contained and he simply couldn’t eat as much as he intended to). Guess what happened? He lost 21 lbs during those 60 days. (source)
- The Potato Diet (Version 2)
Andrew Flinders Taylor, who appears to just be some random dude from Australia, went on a potato-only diet of his own, this time doing it for nearly 1 full year. However, a caloric deficit also existed. Guess what happened? He lost 117 pounds in a year. (source)
There are actually more examples like this where people went on equally crazy diets that involved eating everything from only pizza (source) to only ice cream (source) and, in every single case, they all still lost weight just fine.
The key question is, why is this? And the answer is very simple.
Because weight loss and weight gain are dictated by calorie intake, not by carb intake. Even when you eat tons and tons of carbs – and even when they are the really bad, high sugar, high glycemic kind – fat will still be lost as long as a caloric deficit exists.
There are many real-world examples of people going on extreme diets that consist almost entirely of foods that are very high in carbs and/or sugar – the exact same foods that low carb diets say must be avoided in order to lose weight – and all of those people lost weight just fine thanks to the presence of a caloric deficit.
A List Of Relevant Studies
If real-world evidence isn’t your thing, and you happen to be the kind of person who requires a long list of relevant studies that support a point before you’d even consider accepting that point as truth… then this next section is for you.
Here now is a collection of just some of the studies that support the fact that A) a caloric deficit is the sole cause and requirement of fat loss, B) whether carb intake is low, moderate, or high, fat loss still happens just the same as long a deficit exists, and C) when total calorie and protein intake are controlled for, it makes little to no difference whatsoever how many grams of carbs you eat.
Feel free to check out each study when you have a few hours to kill…
But wait… hang on… I bet I know what you’re thinking now.
“Where Are All Of The Studies That Support Low Carb Diets?!?”
If you’re a low carb dieter or thinking about becoming one, chances are you’ve heard about other studies that support the usage of this type of diet plan.
You know… the studies that support the claim that is it indeed carbs (not calories) that truly dictate fat loss and fat gain. The studies that support the claim that low carb diets are superior to other types of diets. The studies that every well-known low carb guru uses to back up the recommendations they give, the claims they make, and the products they sell.
Where, exactly, are all of those studies?
Am I ignoring them, or insinuating that they don’t exist?
Nope, not at all. These studies absolutely DO exist.
Guess what else? They all happen to have one minor detail in common…
They All Have Serious Design Flaws
Basically, the studies that support the usage of low carb diets for weight loss are flawed to a degree that makes their conclusions inconclusive at best. And at worst? It makes them useless misleading horseshit.
Usually, it’s the latter.
But the low carb world LOVES to cite these kinds of studies. And, well… they kinda have to. Why? Because flawed studies are the only studies where the benefits of low carb diets are ever seen.
Take away those flaws and recreate the same circumstances in a better designed study (like many of the ones on the list from before), and guess what happens? Suddenly, those benefits no longer exist.
So, what kind of design flaws am I talking about here? These are the two biggest…
1. Protein Is Not Controlled For
In studies where a comparison is being done between low carb vs high carb (or low carb vs anything, for that matter), and low carb comes out as the clear winner, it almost always just so happens to be that the low carb group had a much higher protein intake than the other group(s) did.
In fact, the protein intake of the higher carb groups in these types of studies is often below the RDA’s recommendation for protein intake, and damn near everyone in the nutrition field would agree that the RDA’s recommendation is already significantly lower than what’s ideal for someone trying to lose weight (for comparison, the protein intake of the low carb group is typically well above the RDA).
Why is this important, you ask?
Because, as I mentioned earlier, protein plays huge roles in…
- Hunger control (more protein = less hunger = fewer calories eaten = more likelihood of a deficit existing).
- Thermic effect (more protein = more calories burned per day = more likelihood of a deficit existing).
- Preserving muscle (more protein = more muscle = higher metabolic rate = more likelihood of a deficit existing).
Which means, in order to truly tell if it’s the difference in carb intake that is making one diet more effective than the other, you MUST ensure that both groups are eating EXACTLY the same amount of protein. But yet…
In These Types Of Misleading Studies, Protein Is NEVER Kept Constant
Instead, the low carb group always eats significantly more protein than the group(s) it is being compared to. And magically… the low carb diet somehow comes out on top.
Wow, what a surprise!
From there, various low carb gurus find this study and cling to it as proof of their false claims without ever mentioning a word about the differences in protein intake between the diets that were compared, which just so happens to be a design flaw that invalidates the conclusion they are coming to.
Really, if these studies tell us anything useful, it’s that high protein is better for weight loss than low protein. To which everyone already aware of protein’s benefits would say “yeah, no shit.”
What About When Protein IS Kept Constant?
Oh, and if you’re wondering what happens in studies that compare low carb diets to higher carb diets AND ACTUALLY DO keep protein intake the same between groups (like many of the studies I listed earlier), then here’s a little spoiler for you…
In studies that control for both protein and calories (more about that in a second), every group ends up losing the same amount of weight. No benefit is seen with lower carb diets vs higher carb diets. No meaningful difference whatsoever is found between groups despite having higher or lower carb intakes. Basically, with protein and calories being equal, your ratio of carbs and fat doesn’t really matter much, if at all.
Studies that show any benefit or superiority to a low carb diet plan over a moderate or higher carb diet plan usually fail to keep protein constant. And since we already know that higher protein intakes provide a variety of weight loss related benefits, we know that whichever group is eating sufficient amounts of protein is going to come out on top of the group that isn’t. In these flawed studies, the low carb group just so happens to be the one that’s eating the most protein. Which means it isn’t the low carb aspect itself that’s doing anything special in these studies, it’s the high protein aspect. In the studies that DO keep protein intake constant between groups, no benefits are seen with lower carb diets.
2. Calories Are Not Controlled For
Now take everything we just talked about regarding protein intake not being kept the same between groups, and then replace the word “protein” with the word “calories.”
Because that right there is yet another wonderful flaw commonly seen in studies that show any benefit to low carb diets.
See, if we’re trying to determine if it’s calories or carbs that are the true cause of weight loss, or if lower carb diets provide any benefits over higher carb diets… the only way to accurately do that would be by having two groups eating the SAME amount of calories, and then have one group eat lower carbs and the other eat higher carbs.
This way, carb intake would be different, but total calories would remain constant.
Then, if the low carb group ended up losing more fat (or losing fat any better or faster) than the other group, then holy crap… we’d actually have something useful and conclusive!!
Unfortunately, This NEVER Happens In The Studies Touted By The Low Carb World
Instead, it’s just a lower carb diet vs a higher carb diet with little to no attention being paid at all to how many calories the different groups are eating.
Why does this matter so much, you ask?
Well, do you remember earlier when I explained how low carb diets always directly or indirectly involve making other dietary changes (more protein, more fiber/vegetables, more fat) that have significant hunger-controlling benefits? The kind of benefits that lead to fewer calories being eaten?
And how when you remove a ton of carbs from a person’s diet, you also end up removing a ton of calories as well?
Well, if Group A is doing a much better job of controlling hunger than Group B… and Group A has restricted an entire food group that Group B is still allowed to eat… and Group A is therefore going to be eating significantly fewer calories than Group B is… then guess which group is going to end up losing more weight and doing so better/faster/easier?
THAT’S RIGHT!! Group A!
And as it turns out, the low carb group is always “Group A” in these studies.
So again what will happen is that various low carb gurus will find these studies and hold them up high as proof of their false claims without ever mentioning a word about the differences in total calories eaten between the groups that were compared, which just so happens to be a design flaw that invalidates the conclusion they are coming to.
Really, if these studies tell us anything useful, it’s that eating fewer calories and adjusting your diet to better control your hunger is more effective for weight loss than doing the opposite. Once again…. no shit.
What About When Calories ARE Kept Constant?
And if you’re wondering what happens in studies that DO keep calorie intake the same between groups (like many of the studies I listed earlier), then here’s that same little spoiler for you from before…
In studies that control for both protein and calories, every group ends up losing the same amount of weight. No benefit is seen with lower carb diets vs higher carb diets. No meaningful difference whatsoever is found between groups despite having higher or lower carb intakes. Basically, with protein and calories being equal, your ratio of carbs and fat doesn’t really matter much, if at all.
Studies that show any benefit or superiority to a low carb diet plan over a moderate or higher carb diet plan fail to keep calories constant. And since we already know that it’s total calories that dictate weight loss and weight gain, we know that whichever diet leads to fewer calories being consumed is going to end up coming out on top. In these flawed studies, the low carb group just so happens to be the one that’s eating the fewest calories. Which means it isn’t the low carb aspect itself that’s doing anything special, it’s the lower calorie aspect. In studies that DO keep calorie intake constant, no benefit is seen in the low carb group.
So, How Do Low Carb Diets Work?
It’s actually pretty simple.
Low carb diets work by indirectly causing a caloric deficit to exist.
This occurs due to a combination of:
- Removing a ton of calories from your diet by removing a ton of carbs from your diet, and…
- Directly or indirectly getting you to make other dietary adjustments (more protein, more fiber, more vegetables, more fat) that just so happen to lead to significantly less hunger and thus fewer total calories being eaten. (And, in the case of protein, an increased metabolic rate and thus more total calories being burned.)
Or, to put that another way: low carb diets work by getting you to be in a caloric deficit while claiming it has nothing to do with being in a caloric deficit.
You know… just like every other seemingly non-calorie-based diet does.
FAQ: Frequently Asked Questions
Now let’s cover a few remaining questions/comments some people may have…
Q: I don’t care what you say or what evidence you have, the low carb diet works for me!!
That’s fantastic, but it appears you’ve missed the entire point of the article.
Q: I disagree with all of this!! My favorite low carb guru disagrees with all of this, too!!
Wow, I’m so completely and utterly shocked to hear this. I would have thought for sure that you would have immediately changed your opinions, beliefs, and recommendations. The fact that you didn’t is truly hard for me to believe. I don’t know what to make of this. How will I ever find the strength to go on.
Q: What about Gary Taubes and his popular books?
Q: What about insulin? I always hear the low carb people talking about insulin?
I’d recommend checking out James Krieger’s series of articles about insulin starting here.
Q: What about the “type” of carbs we eat? Doesn’t that matter?
Strictly in terms of fat loss and fat gain? And with all else (e.g. calorie intake, protein intake, fat intake, dietary adherence, etc.) being equal? Nope. There’s no meaningful difference. You’ll lose or gain the same amount of body fat regardless of whether the carbs you eat are “good” or “bad” or “simple” or “complex” or “high glycemic” or “low glycemic” or whatever else. (I cover this topic in detail in my comparison of Brown Rice vs White Rice.)
In terms of things like overall health, micronutrient intake, hunger control, and so on, then yes, there’s obviously some degree of difference between eating sugary garbage and eating some kind of higher quality, nutrient-dense carb source.
This is why I recommend comprising the majority of your diet (e.g. 80-90%) with higher quality, minimally processed, nutrient-dense foods, while keeping the fun, lower quality stuff to a small yet still enjoyable and sustainable minimum (e.g. 10-20%).
Q: What if I prefer to use a low carb diet, but not because of any supposed magic of carbs, but because it suits my personal needs and preferences and I find it easier to sustain than other diets? What if I simply don’t care that it’s really just a means of getting me to eat fewer calories? What if I just happen to like it best?
That’s totally fine by me.
Q: I tried this “caloric deficit” thing before and it didn’t work for me. The only thing that ever worked was low carb. Therefore… it IS all about carbs, not calories.
Cool… here’s two reasons for why you’ve come to this incorrect conclusion:
- First, if the “caloric deficit” thing didn’t work for you, it’s guaranteed proof that you weren’t actually in a caloric deficit. At least, not consistently enough for it to work. This scenario – where a person thinks they are in a deficit when they aren’t – is extremely common and occurs most often due to issues in the tracking of calories consumed and/or calories burned which results in the person unknowingly eating more and/or burning less than they think they are/claim to be… and thus no deficit actually exists. This happens ALL THE TIME (sources: here, here, here, here, here, here, and here). So why did low carb work for you instead? Because it allowed you to finally end up in the deficit you unknowingly failed to be in before.
- Second, maybe you did legitimately get into a caloric deficit. But, the rest of your diet was poorly designed, and that made it too hard for you to sustain. Meaning, you were probably consuming an insufficient amount of protein, fiber, vegetables, and/or fat… all of which are things that would have helped you better control your hunger and sustain your deficit. And it wasn’t until you went low carb that you finally started to consume ideal amounts of these other beneficial things, thus making everything better and easier for you. So it wasn’t the low carb aspect of the diet itself that worked for you, it was the other dietary adjustments that came along with it which you could have (and SHOULD HAVE) just as easily made on the previous diet you were using.
Q: But I’m on a low carb diet now and I’m eating TONS of calories from protein and fat. TONS OF CALORIES!! There are literally no limits on the amount of calories I can eat, so there’s no way in hell that I’m in a caloric deficit. I’m eating an unlimited amount of calories and I’m still losing weight just fine. Hooray for low carb!
Yeah, here’s the thing about that. You may not have a literal written limit on how many calories you can eat. On paper, you can seemingly eat unlimited amounts. However, in reality, you’re doing a bunch of things within your diet that will naturally limit how many calories you end up eating.
What I mean is, by greatly restricting/completely eliminating an entire food group – which happens to be the food group that people overeat the most – while simultaneously making other adjustments that keep you significantly fuller for a significantly longer period of time… guess what’s going to naturally happen?
The amount you’re capable of eating WILL be limited whether you realize it or not.
That’s just what’s bound to happen when you’re much less hungry overall and not allowed to eat the most popular food group. So yeah, sure, low carb diets may claim you can eat an unlimited amount of calories. But, at the same time, it’s a diet that is designed to greatly limit how many calories you end up eating.
Q: I’ve decided that I’m going to ignore 100% of the logic, facts, and evidence you’ve presented here. If you continue to try to reason with me in a civilized manner, I’ll literally close my eyes, cover my ears, and yell “LA LA LA LA LA LA, I CAN’T HEAR YOU, LA LA LA LA LA LA!!” Instead, I’m going to cling to a few highly flawed cherry-picked studies that don’t control for calories and/or protein (while again ignoring the studies that do). Then I’m going to appeal to authority by mentioning names like Taubes, Fung, Ludwig, Noakes, Harcombe, and other such people who are widely regarded as a joke by the actual scientific community. Then I’m going to say words like “hormones” and “insulin” and “metabolic advantage” even though, in all honesty, I don’t have a clue wtf they even mean.
From there, my next logical fallacy of choice will be “strawman” at which point I’ll say something like “so you think eating 2000 calories from nothing but sugar is a healthy way to lose weight?!?” or “so you think 2000 calories from cookies is exactly the same as 2000 calories from broccoli and chicken breast?”
After that, I’ll spout some batshit crazy nonsense about government conspiracies, followed by getting really angry and calling you names because I’ve formed an emotional attachment to bad information and I simply don’t know how else to respond at this point. Then I’m going to run back to the safety of my little low carb echo chamber/cult where other people who are just as misinformed as I am will confirm my preexisting biases and make me feel okay again. As an added bonus, I might also tell a few dozen of them to come here and send you angry messages on social media.
Wow. I sooooo didn’t see that coming. Quite frankly, I’m stunned.
Q: What kind of diet do you recommend for losing weight?
It’s pretty simple…
- First, create a moderate caloric deficit. 20% below your maintenance level is a good place to start. Full details here: How Many Calories Should I Eat A Day?
- Second, get a sufficient amount of protein. 0.8-1g of protein per pound of your current body weight is a good place to start (use your goal body weight for this calculation if you are very overweight). Full details here: How Much Protein Should I Eat A Day?
- Third, fill in your remaining daily calories with whatever amounts of fat and carbs you happen to like best so that a) neither nutrient is excessively low or excessively high, and b) your diet is as Preferable, Enjoyable, Convenient, and Sustainable for you as possible (#PECS). Additional details here: How To Calculate Your Macros
- Fourth, get the majority of those nutrients from higher quality, nutrient-dense food sources (while still keeping the yummy fun stuff around as a small part of your overall diet).
- Fifth, put everything else (meal frequency, timing, scheduling, food combinations, etc.) together in whatever the hell way you like best so that, yet again, your diet is as #PECS for you as possible.
That’s it. That’s everything.
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