Why Seemingly All Diets Can Succeed…or Fail
It seems like not a day goes by where we don’t hear about an amazing new diet that will “reset your metabolism” or make you “shed body fat.” Everything is labeled as “fast,” “quick, “overnight,” or my personal favorite: “fat burning machine.”
Even more interesting than the titles of the diets are people’s personal stories on such plans. Occasionally we hear about someone doing incredibly well on one of these diets. Just this past summer I had a friend switch to a vegetarian diet, a family member go keto, and clients at the gym telling me about how they are trying Whole 30, the Fast Metabolism diet, intermittent fasting, or they’ve started the Bulletproof plan. Out of all of those groups, some people lost weight on each protocol, some stayed the same on each protocol, and quite a few people hated the plan altogether and threw it out the window.
Why is it that low-carbohydrate diets work so well for some, but not for others? Why do low-fat diets work well for some, but not for others? Why do elimination diets, resets, or very strict plans work well for some, but not for others?
When I refer to a diet “working well” for someone, I mean: an individual is able to stick to the protocol relatively comfortably, with no major unfavorable changes in mood or mental wellness, and some weight is lost according to their scale at home.
When I refer to a diet “not working well” for an individual, I mean: a person is hungry, irritable, dealing with headaches, unfavorable changes in mood or mental wellness, unable to adhere to the protocol, achieving no loss of weight, or gaining weight according to the scale at home.
I can find people who lost weight on Whole 30, Bulletproof, Keto, Paleo, intermittent fasting, Vegan, Fast Metabolism, The Zone, or Vegetarian plans–to name a few. And I can find people who stayed the same, felt unwell, or even gained weight while trying to participate on all of the aforementioned plans.
Why does it seem like all sorts of diets can make some people lose weight? Sounds like something a nutrition research study should address, doesn’t it? Well, they’ve investigated such questions.
The DIETFITS Randomized Clinical Trial
The DIETFITS randomized clinical trial investigated the effect of low-fat vs low-carbohydrate protocols on 12-Month weight loss in overweight adults and associations with genotype pattern or insulin secretion. There were 609 participants (big sample size for a nutrition study!), and each person was randomly assigned to a high-fat/low-carb diet (20 g of carbohydrate per day) or a high-carb/low-fat diet (20 g of fat per day), and they were monitored closely by the research team dietitians to ensure diet compliance and exercise. Both groups were instructed to eat a diet of whole, fresh foods that’s low in added sugars, zero trans fats, and there was great emphasis to consume foods cooked at home. The outcomes that the team monitored were significant interactions among diet type and genotype pattern, diet and insulin secretion, and diet and weight loss.
The researchers hypothesized that there would be interactions between diet and insulin secretion and genotype pattern.
The results: Both groups lost nearly identical amounts of weight overall. There was no significant difference in weight loss between the two groups at 12 months. There were no significant interactions between diet and 3 SNP multilocus genotype patterns, and no significant changes in baseline insulin secretion after 12-months spent on either a healthy low-fat or healthy low-carb diet.
This study was incredibly well-conducted, and demonstrates that weight can be lost through different programming. What this team really showed is that there are different ways to lose weight–but that you have to reduce energy intake somehow. Reducing carbohydrates or reducing fat and focusing on whole fresh foods can achieve this. They also demonstrated that adherence is the name of the game. Both groups stuck to their plans for 12-months! That’s a long time spent on a specific nutrition protocol.
A study on fasting vs continuous energy restriction discovered something similar.
Effect of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk: A randomized 1-year trial
Svendson et al. placed 112 overweight adults on either an intermittent or continuous energy restriction plan at random. Participants were guided by dietitians via face-to-face counseling for the first 6-months, and then by distance for the last 6-months. The intermittent energy restriction group was advised to consume 400/600 kcal (female/male) on two non-consecutive days, and both groups reduced energy intake by ∼26–28% kcals from baseline. Body weight, waist circumference, blood pressure, triglycerides and HDL-cholesterol were all monitored.
The results: There was no significant difference between weight loss, waist circumference, blood pressure, triglycerides, and HDL-cholesterol; but the intermittent fasting group was hungrier.
Dietary Protocols and Adherence
These studies–and all the folks who lose weight on current trendy diets–illustrate several incredibly valuable points about weight loss. Firstly, it demonstrates that there are different ways to lose weight, but an energy deficit has to be achieved somehow. Diets that cut-out entire food groups are going to put someone in an energy deficit. Diets that promote whole fresh foods and removing processed foods are going to put someone in an energy deficit. Diets that make someone fast several times a week are going to put someone in an energy deficit. And the most successful programs are ones that facilitate long-term adherence for an individual–and for most people, what they can adhere to is going to be unique to them.
This is why we hear about people succeeding or totally imploding on any given diet. There are people who love high-fat diets and feel comfortable sticking to it. Others who exercise vigorously will probably feel better on a healthy diet with adequate carbohydrate intake. And some people get so overwhelmed by healthy eating strategies, that they don’t stick to anything, so a strict protocol works well for them.
But this is also why diet culture is so broken and often fails people. Diets end, because people can’t live on diets, and then they don’t know what to eat when it’s over–which is why we hear about individuals gaining weight after strict diets, binging, and yo-yo dieting. This fact is exactly why people need to learn how to eat, how to exercise, and how to recover. That way, we can create an enjoyable and sustainable lifestyle that captures and maintains a healthy weight and a happy body that lasts for decades to come.
https://jamanetwork.com/journals/jama/fullarticle/2673150
https://www.sciencedirect.com/science/article/pii/S0939475318301005
Why Seemingly All Diets Can Succeed…or Fail
It seems like not a day goes by where we don’t hear about an amazing new diet that will “reset your metabolism” or make you “shed body fat.” Everything is labeled as “fast,” “quick, “overnight,” or my personal favorite: “fat burning machine.”
Even more interesting than the titles of the diets are people’s personal stories on such plans. Occasionally we hear about someone doing incredibly well on one of these diets. Just this past summer I had a friend switch to a vegetarian diet, a family member go keto, and clients at the gym telling me about how they are trying Whole 30, the Fast Metabolism diet, intermittent fasting, or they’ve started the Bulletproof plan. Out of all of those groups, some people lost weight on each protocol, some stayed the same on each protocol, and quite a few people hated the plan altogether and threw it out the window.
Why is it that low-carbohydrate diets work so well for some, but not for others? Why do low-fat diets work well for some, but not for others? Why do elimination diets, resets, or very strict plans work well for some, but not for others?
When I refer to a diet “working well” for someone, I mean: an individual is able to stick to the protocol relatively comfortably, with no major unfavorable changes in mood or mental wellness, and some weight is lost according to their scale at home.
When I refer to a diet “not working well” for an individual, I mean: a person is hungry, irritable, dealing with headaches, unfavorable changes in mood or mental wellness, unable to adhere to the protocol, achieving no loss of weight, or gaining weight according to the scale at home.
I can find people who lost weight on Whole 30, Bulletproof, Keto, Paleo, intermittent fasting, Vegan, Fast Metabolism, The Zone, or Vegetarian plans–to name a few. And I can find people who stayed the same, felt unwell, or even gained weight while trying to participate on all of the aforementioned plans.
Why does it seem like all sorts of diets can make some people lose weight? Sounds like something a nutrition research study should address, doesn’t it? Well, they’ve investigated such questions.
The DIETFITS Randomized Clinical Trial
The DIETFITS randomized clinical trial investigated the effect of low-fat vs low-carbohydrate protocols on 12-Month weight loss in overweight adults and associations with genotype pattern or insulin secretion. There were 609 participants (big sample size for a nutrition study!), and each person was randomly assigned to a high-fat/low-carb diet (20 g of carbohydrate per day) or a high-carb/low-fat diet (20 g of fat per day), and they were monitored closely by the research team dietitians to ensure diet compliance and exercise. Both groups were instructed to eat a diet of whole, fresh foods that’s low in added sugars, zero trans fats, and there was great emphasis to consume foods cooked at home. The outcomes that the team monitored were significant interactions among diet type and genotype pattern, diet and insulin secretion, and diet and weight loss.
The researchers hypothesized that there would be interactions between diet and insulin secretion and genotype pattern.
The results: Both groups lost nearly identical amounts of weight overall. There was no significant difference in weight loss between the two groups at 12 months. There were no significant interactions between diet and 3 SNP multilocus genotype patterns, and no significant changes in baseline insulin secretion after 12-months spent on either a healthy low-fat or healthy low-carb diet.
This study was incredibly well-conducted, and demonstrates that weight can be lost through different programming. What this team really showed is that there are different ways to lose weight–but that you have to reduce energy intake somehow. Reducing carbohydrates or reducing fat and focusing on whole fresh foods can achieve this. They also demonstrated that adherence is the name of the game. Both groups stuck to their plans for 12-months! That’s a long time spent on a specific nutrition protocol.
A study on fasting vs continuous energy restriction discovered something similar.
Effect of intermittent versus continuous energy restriction on weight loss, maintenance and cardiometabolic risk: A randomized 1-year trial
Svendson et al. placed 112 overweight adults on either an intermittent or continuous energy restriction plan at random. Participants were guided by dietitians via face-to-face counseling for the first 6-months, and then by distance for the last 6-months. The intermittent energy restriction group was advised to consume 400/600 kcal (female/male) on two non-consecutive days, and both groups reduced energy intake by ∼26–28% kcals from baseline. Body weight, waist circumference, blood pressure, triglycerides and HDL-cholesterol were all monitored.
The results: There was no significant difference between weight loss, waist circumference, blood pressure, triglycerides, and HDL-cholesterol; but the intermittent fasting group was hungrier.
Dietary Protocols and Adherence
These studies–and all the folks who lose weight on current trendy diets–illustrate several incredibly valuable points about weight loss. Firstly, it demonstrates that there are different ways to lose weight, but an energy deficit has to be achieved somehow. Diets that cut-out entire food groups are going to put someone in an energy deficit. Diets that promote whole fresh foods and removing processed foods are going to put someone in an energy deficit. Diets that make someone fast several times a week are going to put someone in an energy deficit. And the most successful programs are ones that facilitate long-term adherence for an individual–and for most people, what they can adhere to is going to be unique to them.
This is why we hear about people succeeding or totally imploding on any given diet. There are people who love high-fat diets and feel comfortable sticking to it. Others who exercise vigorously will probably feel better on a healthy diet with adequate carbohydrate intake. And some people get so overwhelmed by healthy eating strategies, that they don’t stick to anything, so a strict protocol works well for them.
But this is also why diet culture is so broken and often fails people. Diets end, because people can’t live on diets, and then they don’t know what to eat when it’s over–which is why we hear about individuals gaining weight after strict diets, binging, and yo-yo dieting. This fact is exactly why people need to learn how to eat, how to exercise, and how to recover. That way, we can create an enjoyable and sustainable lifestyle that captures and maintains a healthy weight and a happy body that lasts for decades to come.
https://jamanetwork.com/journals/jama/fullarticle/2673150
https://www.sciencedirect.com/science/article/pii/S0939475318301005