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.
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.
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.
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.
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.
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.
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)?
- The Biggest Loser diet is the bigger badass brother of Eat Less, Move More.
- Eat Less Move More – Proven failure. The Biggest Loser – Proven failure on steroids.
- Bariatric surgery is the bigger badass brother of Intermittent Fasting
- 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….