Do DNA-Based Diets Work?

[T_Nation]

by Chris Shugart

Your Genetic Code and Fat Loss

The most effective diet is based on your individual genetics. Or is it? Here’s what you need to know before you buy one of these plans.

Healthy fat loss is all about consuming sub-maintenance calories, or spending more calories via activity, while keeping protein intake on the higher side. That’s about it. Of course, there are hundreds of ways to do it. The “best” plan for you comes down to preference and adherence.

Yet every few years, someone tries to hack this proven approach. We’ve had diets based on blood types and even diets based on astrological signs. There’s probably a diet based on your favorite Taylor Swift song. And these diets work, at least in the short term, but not for the reasons their proponents say they do. Rather, they work because they all boil down to eating less. Same plot, different novel.

Today, the new “best” diet for you is based on serious science: your genetic code. For $200 to $500, several companies will tell you exactly how to eat for fat loss based on your unique DNA. But does it work? Not really. Or at least not any better than the strategy outlined in the first sentence above. Save your money.

But, But, It’s Science!

It is science. Cool science, even. It just doesn’t seem to make a difference. Here’s some background:

Your genes don’t make you fat; your behaviors do. But there are genetic variations that might make it a little easier to get fat. For example, single-nucleotide polymorphisms (SNPS or “snips”) are found in the DNA between genes. Most are harmless, but some can play a role in disease if they affect the gene’s function. “Snips” of the leptin pathway seem to control hunger and how you burn calories, for example.

Now, the idea behind these DNA-based diets is that people respond better to certain macro ratios:

• Some people have carbohydrate-responsive genes (polymorphisms). They lose more fat on high-carb, low-fat diets.
• Some people have fat-responsive genes. They lose more fat on high-fat, low-carb diets.

Is That True? A New Study Took a Look

Researchers recruited 122 fat people and had them take a genealogy test. Based on 10 genes and their snips, they were deemed fat-responders or carb-responders and placed in a diet group, either a group that “matched” their genes or one that didn’t.

• Group 1: Fat-responders given a high-fat diet. This “matched,” so these folks should lose more weight.
• Group 2: Fat-responders given a high-carb diet. This didn’t match, so these folks should lose less weight.
• Group 3: Carb-responders given a matched high-carb diet, so they should do well.
• Group 4: Carb-responders given an unmatched high-fat diet, so they shouldn’t do well based on their genes.

All groups followed a 12-week plan where they consumed 750 calories below maintenance. The high-carb dieters ate 65% carbs and 20% fat. The high-fat dieters ate 45% carbs and 40% fat. All their diets were made up of 15% protein.

The Results

In a nutshell, the type of diet they were given, gene-matched or not gene-matched, didn’t make much of a difference at all.

The supposed fat-responders given the “right” diet lost 12 pounds, but those given the genetically “wrong" diet lost 11.5, which is statistically insignificant. Same with the carb responders, though there was a two-pound difference there (11 vs. 9) – still not considered significant since the average was 10 pounds, give or take. Also, there were no real differences in blood pressure and other metabolic health markers.

The researchers concluded, “We found no difference in weight loss between individuals on the genotype-concordant vs. genotype-discordant diet.”

How to Use This Info

T Nation contributor Dr. Bill Campbell says that personalized nutrition based on your genetic makeup is the future, but based on this study, we’re just not there yet.

If your fat-loss plan involves eating fewer calories and/or moving more – with the caveats of doing resistance training, eating plenty of protein, and choosing healthy foods – you’ll lose fat.

DNA-based fat-loss plans are, for now, science fiction.

Note: Thanks to Dr. Campbell for summing up this study in his excellent Body by Science newsletter.

Reference

1. Höchsmann, et al. “The Personalized Nutrition Study (POINTS): evaluation of a genetically informed weight loss approach, a Randomized Clinical Trial.” Nature Communications, 2023.

[TrainForPain]

Nice article! While not statistically significant, I’m actually intrigued there was a numeric trend toward the DNA diets (as well as Dr. Campbell thinking there’s potential merit).

[Chris_Shugart]

Yeah, there could be something interesting pop up in the future with DNA/genotype diets, but I’m not seeing it yet, especially at $200 to $500 bucks a pop.

Some other thoughts:

The “mismatched” diets worked almost as well as the “matched” diets: .5 pounds more fat loss in the case of the fat-responders and 2 pounds for the carb-responders. (I think we can disregard the .5 number.)

But I also like to flip-flop the analysis. Think about it: the “wrong” diet worked almost as well. You’d think the results would be very bad if the diet didn’t fit your DNA. Nope, practically the same. And those numbers were averages. Some participants lost MORE fat on the “wrong” diet. So, the calorie deficit is still king here.

But I suppose that taking a scientific test and being told what diet works best is motivating to many people. “It has to work! It’s science! And I paid $500 for it!” So maybe that helps some folks be consistent because they believe in it. Almost like with training. The training plan you really believe in always works better because you try harder and feel good about it.

[TrainForPain]

All really great points. I think the “buy-in” is likely the most important, and the investment may go a second step past “belief”. Almost like when the guy that has never been on a bike buys all the gear before his first ride; maybe the money spent forces him to actually stick with it until he feels like he’s broken even.

Devil’s advocate: one can easily say “the study limitation is duration! Take those numerical losses out long enough and they become significant.” To which I think we can respond, “how long would we expect to see someone in a deficit?” Point being I think the argument with any of these studies that they just didn’t last long enough is silly; we all burn out eventually.

Anyway, I’m with you on the ROI. I think it’s more interesting thought experiment than practical application for most of us.

[Friedrich]

It worked for the model!

[bulldog9899]

So for clarification there’s only been one study regarding the theory?

[Chris_Shugart]

That’s the only one I’m aware of. These DNA-based plans are fairly new. Not sure how many studies you’d need though. In fact, Dr. Campbell posited that a larger study with more people would’ve probably shown an even smaller difference in results (i.e. not 2 pounds in the carb groups, but more like .5 or 1).

Now, I’m open to some other type of DNA-based plans being tested, maybe ones that look at something besides carb/fat ratios. Not sure what that would be. Also, 15% protein for both groups is pretty lame. But I supposed we have enough protein-based studies to tell us what we need to know – most average people need more.

[Chris_Shugart]

The stock photo models?

[Chris_Shugart]

@TrainForPain

Almost like when the guy that has never been on a bike buys all the gear before his first ride; maybe the money spent forces him to actually stick with it until he feels like he’s broken even.

Very true. A person is more likely to stick to a training plan he purchased than a free one, even if that “customized” plan is the same generic plan the coach sells to everyone.

The same is true with some supplements. If you pay $70 for a fat burner you’re probably more likely to stick to your diet plan so you don’t feel like you’re “wasting” the fat burner. And that’s not saying the fat burner is a placebo. Some definitely give you an edge. Just that it adds to the two big overarching factors of diet success: compliance and consistency.

[Friedrich]

[proveyourclaims]

At my age 68, having been a drug-free (although on 100 mg/week test cyp precribed TRT since age 58), non-competitive iron addict since beginning at age fifteen in 1971, I’ve seen far more than what I wish of the marketeering fat-loss industry.

Over those fifty-two years, I’ve witnessed the endless claims of “how to lose bodyfat overnight, easily, painlessly, enjoyably!” and the “now we scientifically really know what causes obesity!” This year’s “the fat-loss answer at last!” unfailingly yields to the “new and improved!” answer in the following years. Since it, of course, appeals to our human desire for “an easy, simple, permanent, once-and-done-forever” solution, that marketing dynamic never changes. The DNA approach is another in that long line.

What hasn’t changed are the profits being earned from the half-true, out-of-context, shrewdly deceptive, carefully-worded claims of the fat-loss industry.

Nor has the physiological fact that sums to “despite genetic variables, situational variables, psychological variables, gut-health issues, hormonal dysfunctions, partitioning variables, digestive and absorptive variables, the reality is that controlling calories consumed/calories burned is how to effectively lose substantial bodyfat”. One person’s variables can mean he/she has to establish a larger calorie deficit than others, but, ultimately, it’s not the diet or menu utilized - - it’s caloric deficit.

Tracking and controlling average weekly calories, as tedious, boring, exasperating, intrusive as it regrettably can be, is exactly how I achieve and maintain a sustainable 10-12% bodyfat for six months of each year; I have again this year, and did so the previous nineteen years. I ensure 0.8 to 1.0 gram of protein per pound of my bodyweight, then consume the balance of daily calories in fats and carbs, eating actual food.

It’s not easy, since it does require consistent self-discipline and long-term patience, yes. Research has provided further data evidencing that the “calories in/calories out” method works, yes. But the method is successful, it’s not at all complicated beyond the “scientific” of reading calorie contents and doing arithmetic, and it’s as ancient a method as Eugene Sandow.

[barley1]

Since the researchers were looking at the effectiveness of diets, measuring fat loss makes sense, but I’m not sure that’s the only measure of success.

It would be interesting to see how different diets affected adherence, cravings, mood, sleep, hormones, etc.

Until recently, I’d mostly been a lower carb kinda guy. Based on some of Thib’s neurotype stuff, I began eating more carbs. I didn’t notice much change in weight, but I did realize how poorly I slept, how anxious, and mildly homicidal I was without carbs. These things matter, too.

[CB123]

I think the study might have missed the point a bit.

It’s unlikely any diet is getting around thermodynamics so actually setting and enforcing a particular deficit in a study is likely to lead to the same fat loss results.

I would think the alleged benefits would be that the person feels like the “custom” diet makes the deficit easier to handle and therefore they actually maintain the deficit or maybe feel more like exercising and thus lose weight through better adherence and more activity.

But it’s hard to measure those points when you’re controlling for calories.

But the fact that there was any difference in the right direction even with calories controlled is pretty encouraging. Maybe they felt better and moved around more.

[Chris_Shugart]

Agreed. But it’s also deceitful for these companies to charge $500 for a diet strategy that claims it’s genetically matched and the “best” for a person based on genotypes. The science (so far) says that even the “mismatched” diets lead to statistically the same results.

Like I wrote in the intro, any diet with a big calorie deficit works, even if we base the macros/foods/eating-times on favorite colors, music preferences, or zodiac signs.

That exists actually, even though I was just making a funny in the article:

I just hope Sagittarius needs more bacon.

[fitafter40]

Watch out for the new A.I. diet to come out by the end of the year, lol

[TrainForPain]

@fitafter40

Watch out for the new A.I. diet

I can think of at least 3 apps that are exactly that now!

[Chris_Shugart]

Let’s ask ChatGPT:

For funsies, I asked it to write a workout plan too. Check it out.