Nutritionism keeps a lot of people fat.
It’s weird to think that a nutrition-focused approach to eating might have a downside, but in this world of diet gimmicks, that’s what we repeatedly see.
Nutritionism is a common theme among diet gurus trying to set their diet apart by emphasizing the importance of niche nutritional minutiae in weight loss. Food choices, caloric dilution, protein intake, and nutrition do play roles in satiation and cravings, and some other minor aspects of weight loss, but putting the focus on these details lets you lose the forest for the trees and stay fat: I’ve seen it happen many times.
Some of the nutritionism restrictions food gurus focus on may well produce weight loss, as restricting whole categories of food usually cuts down on consumption. But it’s far from universal, and often peters out.
For many people, even the best diet based around low fat whole fruits and veggies will leave them heavier than they’d like after a period of initial weight loss. I’ve covered the science behind this initial drop that stops in this article and video.
So how do you know that you’re being conned by a guru spinning nutritionism?
Diet gurus may try to convince you that you can’t gain fat when overeating on fruit (or carbs, or fat). They might say that the, high glycemic index of a food, your fat intake, lack of special magic indigestible bean calories, foods that don’t fit into some special macro-nutrient ratio, the horror-filled dead end of starvation mode, a lack of negative-calorie foods, or some other nonsense is what’s keeping you from weight loss success.
This emphasis on minutiae causes weight loss to stall out because it overshadows what’s actually important – eating fewer calories.
- Mangoes, durian, and dates may be delicious, healthy, and filling, but if you eat enough calories from them you won’t lose weight (and may gain), just as with any other food.
- If you think high-glycemic index russet potatoes are keeping you fat, you might switch them out for lower GI sweet potatoes. When you still don’t lose weight, remember that it’s not the glycemic index of the food that’s at fault – it’s the calories in the potatoes.
- If you decide carbs are evil and decide to go with a ketogenic high-fat diet, just remember that all that fat is packed with tons of calories, and yes, you can overeat on fat.
I’m a huge proponent eating well for health and vitality, and have been following a whole foods vegan diet for 13 years, but as someone who used to be obese and saw the weight loss stemming from initial diet improvements stall out after awhile, I know that nutritional gimmicks are not what’s behind weight loss.
The Science Discrediting Nutritionism For Weight Loss
Weight loss is a heavily researched field, and thousands of well-run studies have taken a look at different dietary strategies to measure their effect on body fat.
The vast majority have found the same thing – what people ate and the macronutrients of those foods (beyond enough protein to preserve muscle mass and increase satiation) had a fairly small impact on fat loss. The only thing that really mattered was calories and adherence.
The Diet Wars Kick Off
A large meta analysis 1 that drew on the results of 48 randomized weight loss trials with a collective 7,286 participants found something likely to surprise most dieters. Though the participants tried diets that were both low and high fat, low and high carb, and with varying amounts of protein, and included Atkins, Zone, Learn, Ornish, Weight Watchers, Jenny Craig, Nutrisystem, and other diets, none of the approaches really mattered. The only thing that mattered was adherence to a calorie deficit over time.
The researchers concluded that, “…weight loss was observed with any low-carbohydrate or low-fat diet. Weight loss differences between individual named diets were small.”
This supports the primacy of caloric restriction over other concerns when the focus is weight loss. You’d be foolish to forget about health concerns while losing weight, but forget about this primacy and there’s a good chance that your weight loss won’t materialize.
Now promoters of some of these diets had a big objection: the participants didn’t always follow their particular minutiae closely enough.
For instance, when seeing the results of several of the studies this meta analysis drew on, Dr. Dean Ornish, creator of the vegan, low-fat Ornish Diet, objected that the participants weren’t eating a low-fat diet that was low enough in fat to match his target. Similarly, low-carb advocates said that the low carb diets weren’t low carb enough. These are fair complaints, but it’s an issue with almost all weight-loss trials. Participants are rarely as devoted to sticking to their assigned diets as researchers would like.
But there is a way to address Ornish’s concern: metabolic ward studies.
Nutritionism vs Locked Up Diet Studies
If you lock someone up and measure all their food and exercise closely, you can know for certain if a metabolic advantage (more fat burned) is created by one style of eating or another.
Obesity researcher Kevin Hall has done just that 2.
In 2015, he published a study (which I covered in a video) where 19 obese men were put in a metabolic ward for six days on a ketogenic diet and another six days on a low fat diet. The low fat portion featured fat consumption of 8% of calories and plenty of processed sugar. The low carb portion used a maximum of 140 grams of carbs per day.
The low-carb diet burned through 53 g/day of body fat, while the low fat burned through 89 g/day of body fat. So by the end of the study, the low fat group had lost 1.17 pounds of fat, vs .70 pounds for the low carb group. Although this is certainly an advantage, and I do suggest people go with a lower fat diet for this reason and others, it’s not a deal breaker for reasons we’re going to cover shortly.
But low carb and ketogenic diet supporters objected (rightly, I think) to these findings, saying that they didn’t mean anything because although the low carb diet which was tested was low in carbs by the standard of the average western diet, it was not truly ketogenic. They also objected that the six days participants spent on each diet wasn’t enough to draw conclusions.
So NuSI, a nonprofit that exists to fund research related to the carbohydrate-insulin hypothesis (i.e., ketogenic and low carb diets), ponied up the money for independent obesity researchers to do a longer study of a diet that was truly ketogenic.
It put the participants on each diet for a month. But this time, it wasn’t low fat vs lower carb, it was ketogenic vs moderate fat/moderate carb. Surely, a ketogenic diet should whip the pants off an average macronutrient ratio diet with plenty of sugar, right?
The Low-Carb Metabolic Ward Rematch
Seventeen overweight or obese participants were kept in a metabolic ward for eight weeks with all their food provided 3.
During the first four weeks, they ate a moderate carb, high sugar diet with 50% of its calories from Carbs, 15% from protein, and 35% from fat.
For the second four weeks, they ate a ketogenic diet with 5% of its calories from carbs, 15% from protein, and 80% from fat.
The studies provided an equal amount of calories on both diets.
During the moderate carb diet phase, participants lost 1.1 lbs of body fat. During the ketogenic diet, although weight loss from water (due to carbohydrate depletion) was rapid, fat losses amounted to only 0.4 lbs of fat during the first two weeks. Fat loss sped up slightly to 0.7 lbs during the second two weeks.
So during the theoretically metabolism-boosting ketogenic phase, the volunteers lost the same amount of body fat in one month that they lost in two weeks on the higher carb diet.
So it looks like the ketogenic diet does not provide a metabolic advantage over a high-sugar, moderate fat diet, let alone a low fat diet.
The authors concluded that, “…our data do not support the carbohydrate–insulin model predictions of physiologically relevant increases in (energy expenditure) or greater body fat loss in response to an isocaloric (ketogenic diet).”
Further confirming this is a recent meta-analysis by Hall of 32 controlled trials 4 that used same-calorie substitution of carbohyrate for fat. It found that energy expenditure was 26 calories a day higher, and fat loss was 16 g/day greater on lower fat diets.
The researchers concluded that, “These results are in the opposite direction to the predictions of the carbohydrate-insulin model, but the effect sizes are so small as to be physiologically meaningless. In other words, for all practical purposes “a calorie is a calorie” when it comes to body fat and energy expenditure differences between controlled isocaloric diets varying in the ratio of carbohydrate to fat.”
NuSI Tries Again
Just because a ketogenic diet doesn’t offer a metabolic advantage over a month-long period doesn’t mean that it can’t give one over a longer period of time, although this seems fairly unlikely based on the data we have.
Another advantage low carb diets may have outside of controlled feeding trials is by spontaneously causing people to eat less food. We’ve got some data indicating that they may do this, although the effect may be caused by some people eating more protein on lower-carb diets 5.
So once again, NuSI (the nonprofit that funds low-carb research) ponied up money for a longer-term study, but this time without locking people up in a metabolic ward. It selected Christopher Gardner, a professor of medicine at Stanford University, to lead the one-year study, which was called, “DietFits”6. It randomly assigned 609 overweight or obese people to follow either a low-fat diet or a low-carb diet, with both emphasizing minimizing sugar and flour while eating mostly whole foods.
Besides investigating if a low fat or low carb diet lead to a fat-loss advantage outside the lab, it also wanted to explore the large variations seen in weight loss trials. Who might two participants lose vastly different amounts of weight on the same diet?
So what happened? Participants lost an average of 13 pounds regardless of what diet they were on, but as is usual with such studies, the results varied dramatically. Some participants lost 60 pounds while some gained 20.
But there was a big caveat here. Just like the vast majority of non metabolic ward studies, participants did a pretty horrible job of sticking to their diets. After a year of dieting, macronutrient distribution was 48% vs. 30% carbohydrate, 29% vs. 45% fat, and 21% vs. 23% protein for low fat and low carb, respectively. In other words, while there was a solid difference, these were not low fat nor low carb diets.
So, like almost all prior in-the-wild diets studies, proponents of particular diet nutritionism focuses were not satisfied with adherence. But some of the findings were interesting none the less. First, the researchers determined that while there was a huge range of weight loss loss or gain outcomes, neither insulin resistance nor genetic genotype patterns – thought to possibly predispose someone to better outcomes on low carb or low fat diets – actually played a role in a person’s weight loss outcomes.
In other words, it didn’t matter what diet they were on, how messed up their insulin response was, or what was in their gut microbiome. The only thing that mattered was maintaining the diet and cutting calories.
Get Your Head In Gear
When you find yourself telling yourself that something you’re going to eat doesn’t count because it’s a magic food that matches a guru’s magical nutritionism weight loss diet, your mind is in the wrong place. Whenever you rely on magic for weight loss, you’re probably about to get burned.
Diet gurus can produce unlimited success stories supporting their brand of magic short cut, but it’s consistency over the long run that will actually get you the body you want.
When it comes to weight loss, don’t over think your diet, and don’t lose sight of the of the forest for the trees. If you want to lose body fat, eat fewer calories from whatever foods you’re eating. Sure, making healthier food choices may do this automatically for some, as I’ve discussed before. But such losses usually stall out before our ideals are reached.
So when your weight loss is stalled, you’re not “doing something wrong,” in the diet adherence realm, you’re just not concentrating on the right thing – calories.
There’s nothing wrong with eating a healthy diet, but when eating more of the good things becomes eating more calories, things won’t work out.
Johnston, Bradley C. Et al. Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults: A Meta-analysis. September 3, 2014. JAMA. 2014;312(9):923–933. Link.↩
Hall, Kevin. Et al. Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity. Cell Metab. 2015 Sep 1;22(3):427-36. Link. ↩
Hall, Kevin. et al. Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men. Am J Clin Nutr. 2016 Aug; 104(2):324-33. Link.↩
Brehm, BJ. Et al. The role of energy expenditure in the differential weight loss in obese women on low-fat and low-carbohydrate diets. J Clin Endocrinol Metab. 2005 Mar. Link.↩
Gardner, Christopher D. Eta l. Neither Insulin Secretion nor Genotype Pattern Modify 12-Month Weight Loss Effects of Healthy Low-Fat vs. Healthy Low-Carbohydrate Diets Among Adults with Obesity. Circulation. 2017;135:AMP052, originally published March 7, 2017. Link. ↩