The Biggest Loser Diet – Eat Less Move More's Bigger Badass Brother – Fasting 22

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The Biggest Loser is a long running American TV reality show that pits obese contestants against one another in a bid to lose the most weight. The show regularly comes under fire from physicians and other health professionals for its over the top portrayal and its fat shaming tactics. A bit of a surprise, then, at how high this diet actually scored in the 2015 USA Today’s rank of best diets to follow. The Biggest Loser Diet scored #3 under the Best Weight Loss category. Shocking. Nevertheless, like a horrific train wreck, it is difficult to avoid watching this show at times and this is why it continues to air new episodes.2015-1125-NBCUXD-The-Biggest-Loser-KeyArt-Image-1920x1080-UG

First, a bit of background on the actual diet and exercise regimen. Classic Eat Less, Move More. Surely something like this is a good thing, right? What could go wrong? All the ‘experts’ recommend this weight loss regimen. Well, Kai Hibbard, the winner of season three is quoted as saying, “It was the biggest mistake of my life”. Season two’s Suzanne Mendonca says that the reason there’s no reunion show is that “We’re all fat again”. Much of this ‘reality’ series is actually fairly scripted, but this is not the first or last reality series to have that fault.

Luckily, there has been some serious studies done on The Biggest Loser contestants. Dr. Ravussin and Kevin Hall published some fairly extensive metabolic testing on 16 of these contestants. There was a dietary intervention combined with an exercise component. The exercise consisted of 90 minutes per day of vigorous circuit training +/- aerobic training for 6 days a week. This part is often depicted on television, along with some rather questionable fat shaming/ yelling/ screaming by the personal trainers. The exercise portion sometimes far exceeded the allotted time. The fact that vomit buckets were regularly used is an indication that these contestants were pushed quite hard. During their stay on the ranch the minimum time doing physical activity was 2 hours per day.

The dietary component consisted of a calorie restricted diet which was calculated as being about 70% of their baseline energy requirements. Calorie counts often run to 1200 – 1500 per day but it depended upon baseline weight. At baseline, the average weight was 149.2 kg (329 pounds) with a BMI of 49.4. By week 30 (the end of the show’s season), the average weight had dropped to 91.6 kg (202 pounds) – 127 pounds on average! Body fat had dropped from 49% to 28%. Wow. That’s good. Really really good.BiggestLoser1

The benefits went beyond that. Measurements of blood glucose, insulin sensitivity had improved. Much of the weight lost was fat, not muscle. This is likely due to the intensive exercise regimen undertaken. While there was some loss of lean mass, it was not much and the majority of the rather impressive weight loss was, indeed fat.

So, essentially the Biggest Loser diet is Caloric Reduction and Increased Exercise. It’s no wonder the ‘experts’ at US News loves this diet. It is the same Eat Less Move More approach espoused by nutritional authorities everywhere. The Biggest Loser is simply Eat Less Move More on mega doses of steroids. It is the same essential diet, just bigger and badder. Eat Less Move More – looks OK, a little wimpy. Biggest Loser Diet – total badass.BiggestLoser2

These results are starting to look pretty damn good. So why did all those Biggest Loser contestants gain all their weight back after 6 months? Why do all the Eat Less Move More patients gain all their weight back after 6 months? This is essentially the same question. The simple answer is that metabolic adaptations cause that regain. Specifically, metabolism slows down in response to Caloric Reduction. You start to burn less energy. Your metabolism shuts down.

Let’s see what happened to the Biggest Losers. Virtually all of the contestants slowed down their Resting Metabolic Rates (RMR). The energy they use over 24 hours doing no exercise drops significantly. This is energy that is needed to keep the heart pumping, the lungs breathing, your brain thinking, your kidneys detoxing etc. – your basic metabolism. It drops. Like a piano out of a 20 storey building.

To give you a sense of the magnitude of the drop, from start to week 30, the RMR dropped by 789 calories on average. Now that’s not quite accurate, because as your body weight drops, the RMR is also expected to drop. That is, carrying around all that extra fat still takes some energy. If you correct for this weight loss related drop in RMR, though, there is still an excess of 504 calories drop. That is, their metabolism is burning 500 calories less per day than expected correcting for their new, lower weight.BiggestLoser4

But can’t you make up for this decreased in RMR by increasing exercise? Well, no. Despite a massive increase in the amount of exercise performed by contestants, it was simply not enough to overcome the drastic slowdown in metabolism.

Once you stop having Jillian Michaels screaming in your ear about how she doesn’t care if you die on the treadmill, the amount of exercise gradually decreases which further exacerbates the weight regain. From week 6 to week 30, physical exertion goes down. But resting energy expenditure (your metabolism) continues its slide downhill. A double whammy.

As you start burning less energy at rest and burn less energy doing exercise, you get the very familiar weight plateau. The weight loss simply stops because your body has shut down to match the lowered caloric intake. Once expenditure drops below intake, you start the even more familiar weight regain. Ba Bam! Weight regain. Goodbye reunion show.

So, here’s the thing. All of this is completely predictable. Since the Caloric Reduction as Primary strategy has a known 99% failure rate, it’s no surprise that the Biggest Loser diet should also have a similarly dismal outlook. So are we doomed to a life of muffin tops? Hardly. There’s another strategy that seems to be far more successful. Intermittent fasting’s bigger, badder surgical cousin – the gastric bypass. These are stomach stapling surgeries that basically force people to fast. The fasting is not quite intermittent, but rather continuous for several months, until the stomach re-expands. The difference is that fasting allows for the numerous hormonal adaptations that keep resting metabolic rates elevated and preserve lean muscle. We’ve talked (incessantly) about the hormonal adaptations to fasting that seem to be highly beneficial. Decreased insulin. Increased growth hormone. Increased adrenalin. These help maintain resting metabolism so that energy expenditure does not decrease.BLvsRYB2

Hey! We should compare the two strategies directly! Luckily, that study has already been done. Researchers matched 13 gastric bypass patients with 13 Biggest Loser contestants. They lost a similar amount of weight, although the Biggest Loser contestants maintained their lean mass much better – likely due to intensive exercise. So they should do better, right?

Not at all.

By six months, the Biggest Loser group had significantly dropped their metabolic rate. While the bypass group did also do so initially, by 12 months the metabolic rate had gone right back up to normal.

Other studies support the metabolic benefit of intermittent severe caloric reduction.  Looking at the long term metabolic effect of bariatric surgery, researchers found that 14 months after surgery, the total energy expenditure had dropped by 25%. However, when compared against the expected decrease due to the weight loss, there was no decrease in RMR. As I’ve mentioned before – the difference between daily Caloric Reduction and intermittent fasting is that the hormonal adaptations of calorie reduction is to reduce energy expenditure whereas that of IF is to maintain it.Metabolism PostBypass

This makes a huge difference to the long term outcome of patients. If you reduce your metabolism by 500 calories per day, that means that you are going to be feeling cold, lethargic, and tired because your body has started to shut down.  Suppose you start by eating 2000 calories per day. Using Eat Less Move More, you reduce that to 1500 calories per day. Pretty soon, your body is only burning 1500 calories per day. You feel lousy. So, as you increase your calories slightly to 1700, you are still eating less than you used to. But now you are gaining weight. Your body weight goes back up to its original weight as your friends and family silently accuse you of cheating on your diet.

Notice that we are not breaking any ‘Laws of Thermodynamics’. Calories In Calories Out still holds. The point, of course, is that Calories Out is the far more important and decisive factor. However, we focus obsessively on Calories In, which is largely useless. Reducing calories in only reduces calories out.

So, what can we learn from the disaster known as The Biggest Loser? Or the even bigger disaster know as Eat Less, Move More (Caloric Reduction as Primary – aka CRaP)?

  1. The Biggest Loser diet is the bigger badass brother of Eat Less, Move More.
  2. Eat Less Move More – Proven failure. The Biggest Loser – Proven failure on steroids.
  3. Bariatric surgery is the bigger badass brother of Intermittent Fasting
  4. Bariatric surgery – proven success, but with surgical complications. Intermittent Fasting – proven success over thousands of years. No surgical complications.

Pretty clear to me which diet I would choose….

2017-09-02T11:54:10+00:00 33 Comments

About the Author:

Dr. Fung is a Toronto based kidney specialist, having graduated from the University of Toronto and finishing his medical specialty at the University of California, Los Angeles in 2001. He is the author of the bestsellers ‘The Obesity Code’ and ‘The Complete Guide to Fasting’. He has pioneered the use of therapeutic fasting for weight loss and type 2 diabetes reversal in his IDM clinic.

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33 Comments on "The Biggest Loser Diet – Eat Less Move More's Bigger Badass Brother – Fasting 22"

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Victoria West
I don’t see how bariatric surgery = intermittent fasting. It seems to me that bariatric surgery is continuous severe calorie restriction and not intermittent. People who have had these surgeries are physically unable to eat at their TDEE for a few years (unless they live on milkshakes) unlike people who fast. Plus people who have had bariatric surgery usually regain half of their initial weight loss after 5 years. Dr. Jason Fung: Bariatric surgery is not like intermittent fasting. It is like continuous fasting, IF’s bigger brother. Thanks for pointing out. I’ll update the post to make this point more… Read more »
No, it’s not fasting or being unable to eat at TDEE for several years. Yes, initially you eat less, but that lasts a few months and with the protein shakes most Bariatric patience drink, the overall caloric amount isn’t that low. It’s not fasting either, except maybe in the first few weeks. I speak from personal experience. I initially lost 80 pounds of the 100 I was overweight. Then, I began to gain (and It wasn’t from drinking milkshakes or eating what’s considered empty calories foods). I now follow a strict ketogenic diet with intermittent fasting. It’s the only way… Read more »

I knew it !

Dear Dr. Fung, I love your site. I have watched and read just about everything. But I still have a few questions. 1. If I do IF, say 16/8. My hunger drops. Since everyone advises not to eat when not hungry, if I follow this advise and do a 16/8 fast every day my caloric consumption will go down. My insulin resistance may get better but my RMR is going to fall. Won’t it? 2. The forced fasting of gastric bypass is really forced calorie restriction isn’t it? Again this is great for IR and Diabetes but would it not… Read more »
Noam Arif

Thanks for another interesting post, Dr. Fung.

Someone following a 16:8 style of fasting, will easily end up with around 1500 calories pr day. Are those 16 hours enough to give the hormonal benefits you have mentioned?

I guess the worse type of diet is high carb, calorie reduced, frequent eating style?


What would be the best strategy for these contestants at the end of the show to avoid this weight rebound? How can they keep the weight off and rev up their metabolism? This would be worth a look at. Get these show ponies to give a real health benefit.

After successfully gone through “biggest loser”, interested contestants ought to switch to a proven weight maintenance /reduction program, like IF 2 days a week…. Or see below what John C did in his post. I understand that “eat nothing during fast” is the key to release HGH which ups resting metabolism instead of reducing it that lower calories do. And the normal eating 5 days would replenish nutrient stores and ovoid long term divergences, but would best be low in (fast) carbs to reduce blood sugar ups and downs. But obviously it is better to simply start with IF from… Read more »
I believe Dr David Ludwig’s group has done a study that could help clarify your question. They made overweight individuals lose about 15% of their weight through caloric restriction, then placed them on either low fat, mediteranean or low carb diets for maintenance after 4 weeks stabilization period. The Low Carb group’s basal metabolism was 300kcals higher than low fat and the mediteranean group was in between. The take-home seems to be be that, regardless of how you lose weight, lowering carbs seems to be a successful strategy to mitigate metabolic slowdown. I mean.. we’re talking about the equivalent of… Read more »
This is an interesting study you cite here. I viewed Pilon on the subject and he cites studies showing a metabolic slowdown of 120 calories with women doing 500 cals per day for 5 weeks and they lost 16lbs. He maintains the metabolism drops to what it should be for the new weight, this is the notion of metabolic slow down. Initially the heavier weight, being obese has a higher metabolic rate associated with it. What is more the obese who lost weight had a new Metabolic Rate slightly higher than women who are naturally at that same weight.… Read more »
Martin Willias

Dr Fung: I know that you value LCHF as a protocol, but how do you feel about ketosis? Is it necessary? Or is just cutting way down on carbs sufficient?

John C
I reversed my type 2 diabetes on a calorie-restricted, low fat diet, but it was also relatively low carb too, simply because it was low EVERYTHING. I was afraid the significant weight loss would all be regained, just as it had in the past, so I was very interested when I found Dr Fung’s blogs and I enrolled in the Long Range Intensive Dietary Management program. Now, sixteen months later, I have lost even more weight and am stronger and fitter. Thanks to the guidance and encouragement from Megan, I have used a variety of intermittent fasting durations – mostly… Read more »
John, How do you do a day fast? Eat dinner one day, then don’t eat dinner again until the next day? My current structure is to eat dinner Sunday, then no food Monday, then eat dinner Tuesday night. Then I do about 16:8 on Wednesday, don’t eat until dinner on Thursday, then 16:8 Friday and Saturday. Sunday, I usually have three meals, as we go to breakfast after church. I’m trying to be home with the family on Tuesday and Thursday, so it seems a bit silly not to eat at that time. (I was doing three day fasts, eat… Read more »
John C
Bobm, Sorry for the delayed response. My commonest 24 hour fast is between dinner one day and dinner the following day. I used to try doing this Monday-Tuesday, Wednesday-Thursday and then from lunch Friday to lunch Saturday. Sunday was a feasting day with a traditional British roast dinner. On non-fasting days I would usually eat only lunch and dinner, which worked out for me as an 18:6 variant of 16:8 intermittent fasting. If my blood glucose level were particularly low in the morning and I had to drive somewhere, I would eat breakfast for safety but then skip lunch. I… Read more »
Andrea Chang

John C,

When your fasting, do you drink just water? When I fast I drink fruits and veggetables juices. No fiber, just the water from them. Is that ok or do I need to make some changes?


@andrea – that’s not fasting, that’s drinking a bunch of sugar. When you remove the good fiber, sugar is basically what you’re left with.

I would avoid bariatric surgery at all costs because of the downstream effects: diminished absorption of nutrients, meaning you can no longer eat enough food to obtain the proper amount of nutrients to keep your body healthy. You don’t have to be a glutton or anything to obtain proper nourishment, but in the end, you have about 2T. worth of food you can eat before you barf. Such a life! One vitamin pill will pretty much fill you up for hours. Then, there’s the surgical complications…then, the post-op complications…they all add up to a giant NO THANK YOU. Considering the… Read more »

Bariatric surgery is definitely NOT intermittent fasting, and it IS definitely calorie restriction. The difference between a successful bariatric surgery and the biggest loser is less exercise, smaller stomach, calorie restricted for longer than the duration of the show and slowly increasing calories when stomach distends again as opposed to eating anything that doesn’t run away at the end of the show. The idea of comparing the two methods of losing weight is awesome. The conclusions of the article – not so much.


Agreed. This is the first article in your blog, Dr. Fung, that has not made logical sense to me.

What works. Some form of intermittent fasting and ketogenic works for me. What works for one person may help or may not but add all the ns of one and trends emerge “Fasting” for me every other day is bone broth two cups of between 500 to 600 keto ratio calories seaweed Hebrew national hot dog in chicken broth ans salsa and sour cream. Eat day is 1800 calories times am and pm feed. Again very keto 6 grams and 12 grams of carbs respectively and protein about 60 grams each very keto Eric Experiment with protien for yourself up… Read more »

On the topic of reality shows I wonder about Survivor. Seems like the perfect test platform for caloric restrction versus fasting! After digging into Dr Fung’s work I wonder if contestants would suffer less if they DIDN’T eat the meger beans and rice provided and simply fasted.

Dear Dr. Fung, Greetings. I’ve been following your blogs and have been on LCHF for the last 5 months. I have two questions. 1. Elizabeth (from South Africa) mentions in her letter that she realized from your website that Metformin should not be taken on fasting days. I could not find the reference for that. Could you please explain why we Metformin should not be taken on fasting days? 2. Your analogy of the freezer in the basement makes a lot of sense. My question is about the HF part of LCHF; if I keep eating an HF diet, how… Read more »
Intermittent fasting works, low carb eating without worrying about calories works. I am a Type II diabetic who was on two medications plus insulin once/day before I began reading Dr. Fung’s site and researching the concepts he mentions here. Four months ago, I was 100 pounds overweight and I have lost 40 lbs and no longer need any of my medications, including insulin. It is as easy as avoiding carbohydrates (I eat plenty of fresh veg and protein and fat) and eating either 1 or 2 meals/day. I feel great and my endocrinologist (who I sometimes refer to as an… Read more »
Kathy heffner

I am a person who has had a kidney transplant and became diabetic after Trans. I shoot insulin and after 4 years have am very resistant. Pick gained roughly 60 lbs after Trans and becoming diabetic. I can lose wt. I am on prednisone and anti rejection drugs. I have high blood pressure now to and I take three meds for that. I want to fast and try to help myself lose wt. can this be done with these meds that Iam on.

Andrea Chang


I’ve heard of people fasting with their meds and as they got better, their doctors would reduce their meds until they no longer used it. And I’ve also heard of people who just refused to take meds and fasted. I guess it depends on your current condition, so you should consult with your doctor any precautions to take while fasting.


I had being slave of hcg diet for almost 4 years. I cant see any result like losing weight for 5 weeks , my question is can I switch to low carb from hcg?

Thank you



Isn’t the final phase of the HCG diet essentially a couple weeks of low carb/high fat diet? Seems like it would be natural just to continue that.

Main question is this : what’s the difference between fasting and not fasting but doing HIIT and resistance training? Both have similar hormonal response (growth hormones, glycogen depletion, increase in insulin sensitivity). Does fasting achieve a similar but much stronger response? Second question. I guess would you suggest to eat back most calories from exercise to prevent CR, since it lowers metabolism. Final question. What’s the difference between long term fasting at 600 calories/day vs long term eating 1500 calories a day (moderate CR) + expending 900 calories with exercise every day (biggest loser way)? Wouldn’t it trigger a similar… Read more »
So basically all those people eating 1000 calories and barely losing weight could, out of stubborness, drop calories again and again until they unconsciously enter fasting numbers at 500-600 calories/day. So they will think all this time it was CR and not fasting that made them break a plateau. They’ll think they just had to be patient. It goes down to a breaking point at which the body finally says “ok dude you win, I’m gonna go for that fat reserve in the basement and cut the lock with an axe”. Insulin lowers progressively and RMR gets faster accordingly. It’s… Read more »

[…] don’t agree with them. The studies, though were very well done. I’ve written about the Biggest Loser diet previously, but here’s some expanded […]


[…] is that resting metabolic rate (RMR) decreased to LESS than was expected at the new body weight.Check out Dr Jason Fung’s blog post here for more detail  and […]


[…] The Biggest Loser Diet – Intensive Dietary Management – … at how high this diet actually scored in the 2015 USA Today’s rank of best diets to follow. The Biggest Loser Diet scored #3 … Let’s see what happened to the Biggest Losers. … Eat Less Move More’s Bigger Badass Brother – Fasting 22 … […]

Dr. Fung First, thank you. I’m a recently diagnosed T2, with no intention of going the trad medical route of insulin, metformin, etc. I was on the cusp of going some place bad, but through the tips I’ve gleaned on this site and the wonderful youtube videos of you everywhere I’ve been able to bring my MFBG down from the 124-159 range to the 98(this morning)-119 range. And I’ll continue to work on bring it down closer to normal. Slippery slope avoided! Anyway, I had a question about this blog post. You talk above about how the Biggest Loser contestants… Read more »

I’d like to see someone go on the Biggest Loser, ignore the “calorie restriction” diet advise and use fasting as their weight loss method.