It finally happened. A researcher was curious enough to see what happened metabolically to the people who went through the rigorous diet and exercise routines that must be followed on the show “The Biggest Loser” several years later. The results were sobering but unsurprising. The researcher, Kevin D Hall and his colleagues, published their study in the online journal Obesity. The conclusions they came to was that most of the contestants gained most of the weight back (only one contestant has been successful at keeping off all of the lost weight), but even more disheartening was the fact that all of the contestants ended up with a slower metabolic rate after the show than before. Collectively, the metabolic rate was lower by 500 calories a day. As an example, if a contestant was able to maintain his weight of, let’s say, 200 lbs on 2,500 calories a day before he did the intense 7 month diet and exercise regimen, he would struggle to maintain the same 200 lb weight on 2,000 calories afterwords. Danny Cahill, the contestant who started “The Biggest Loser” weighing 490 lbs, finished the show weighing 191 lbs (Admittedly, this is a remarkable feat, and he looks fantastic in his after photos. You can see them here), but he now burns 800 fewer calories a day than someone who has not dieted but weighs the same 191 lbs.
I first learned about this study by my good friend and staff trainer, Josh, and I intended to write a blog simply based on the findings of the lower metabolic rate, and I still intend to do so. However, I wanted to garner more information on the study so I dug deeper, and I found some fascinating insights that were not mentioned in the NY Times article that I believe are relevant in changing the tide of obesity. I will explore these findings first, and then finish with my recommendations.
The effect of extreme diet and exercise on fat-free mass. It is theorized that fat-free mass has an impact on the basal metabolic rate. More specifically, the more muscle mass an individual has, that more calories he will burn, even at rest. So, in theory, if the contestants had a lower resting metabolic rate (I will refer to it as RMR from now on), they should have lost some muscle. Here is what the study has to say:
- Fat free mass at baseline: 75.5 ± 21.1 . Fat free mass after 30 weeks (the biggest loser contest): 64.4 ± 15.5. Fat free mass 6 years later: 70.2 ± 18.3.
For the sake of simplicity, I will use the first set of numbers for all of the stats. Fat free mass at baseline, before the contestants started the strict regimen, was 75.5 pounds. After the contest was over, the fat-free mass was on average 64 lbs, and 6 years later it was hovering around 70 lbs. What I find of interest is that the contestants lost fat-free mass during the contest, even while exercising. In other words, they lost muscle. I am sure that part of the regimen included strength training, but I also know for a fact that the show had the contestants exercising upward to 7 hours a day, mostly in the form of aerobic exercise. There is no question that these contestants were in an over-trained state.
Moving on, the contestants all gained back some fat-free mass after the contest, but not all of the fat-free mass that they had before the contest: 75 lbs before the contest as compared to 70 lbs afterword, yet the RMR has not improved. This is counter-intuitive to my belief that more muscle means more calorie burning and a higher RMR. It shows me that there is more to RMR than just muscle. Clearly there are hormonal factors as well. Having said that, I also suspect that in spite of the strength training the contestants did for the show, they really did not work the deeper fast twitch fibers that they are capable of developing. The reason I say this is because they could not have done a hard strength training workout…and six more hours of chronic exercise everyday and especially on a low-calorie diet. It explains why the contestants lost fat-free mass during the contest, and I theorize that the contestants gained other fat-free mass back after the contest besides muscle. I don’t doubt that they gained some muscle, but they may have gained some water weight as well.
The researchers, on the other hand, remarked that the contestants did gain some muscle back after the six-year lay off, but that they all were well below baseline. I concur, and this can be reason enough for the lower RMR.
Total Energy Expenditure decreased for the same amount of exercise. Total Energy Expenditure, or TEE, was 3,804 ± 926 at baseline, and it was 3,002 ± 573 right after the strict diet and exercise regimen. This is in alignment with the observations of the researchers. To put it succinctly, in spite of all of the hard work and sacrifice that these contestants put into their weight loss efforts, it is clear that they will from now on burn 500 fewer calories a day for the same amount of exercise. Talk about a downer. TEE did improve after six years. It jumped back up to 3,429 ± 581, but it was still lower than before the contest began.
Resting Metabolic Rate (RMR), dropped significantly after the contest, and it did not return to baseline after 6 years. The resting metabolic rate at baseline was 2,607 ± 649 kcal/day, and it dropped to 1,996 ± 358 kcal/day at the end of the 30-week competition. Moreover, it stayed about the same six years later (704 ± 427 kcal/day below baseline). It is the resting metabolic rate that will consistently burn the majority of the calories an individual will consume on a daily basis, and a key factor in weight maintenance.
Leptin and triglycerides remained lower than baseline six years later. The hormone Leptin is produced by the fat cells. Leptin production increases whenever the fat stores increase, and the main function of Leptin is to send the signal to the brain whether there is enough fat stored or not. In other words, more Leptin will send feelings of satiety, thus curbing appetite. Lower Leptin levels will have the opposite effect. What this study shows, though, is that after an extreme diet and exercise program Leptin levels will stay low even when the body starts to store more fat. Consistently lower Leptin levels will keep the hunger pangs high. This is one of the hardest challenges of chronic dieters.
Insulin sensitivity did not improve six years after the competition, even at lower sustained weight loss. Insulin insensitivity is a precursor to both diabetes and obesity, and the fact that there was not an improvement of insulin sensitivity after weight loss is concerning.
The good news for the contestants of The Biggest Loser is that triglycerides stayed low. High triglycerides have been shown to increase the risk of heart attack. Concurrently, both high density lipoproteins (HDL) and adiponectin increased. HDL is the “good cholesterol”, in that it helps in the prevention of heart attacks. Adiponectin has been shown to help the body regulate glucose and fatty acid oxidation. Just like Leptin, it is secreted from the fat cells and acts as a regulatory mechanism for fat storage or fat burning. The more adiponectin that is in circulation, the better the environment is for fat loss.
In summation, even though there were many negative adaptations to the extreme diet and exercise intervention, mainly a lower overall metabolic rate and no improvement on insulin sensitivity, there were some improvements that can help in sustained weight loss and healthier blood markers.
The “Set Point” Theory
This brings us back to the “set point” theory I wrote about in a previous blog. You can read it here. The basic premise of the set point theory is that the body has a certain set point of muscle and fat it wants to hold, and it will do anything in its power to maintain that set point. In other words, when an individual wants to lose fat and goes on a diet and exercise routine to achieve that goal, the body will slow down the metabolic rate thus making it harder to maintain the fat loss and easier to gain the fat weight back with fewer calories than before she started the diet.
During the discussion, the researchers confirmed that this is, indeed, an example of the set point theory in play. Interestingly they contrasted the slower metabolic rate of the contestants of The Biggest Loser to obese people who went through gastric bypass surgery, who were able to still lose weight after one year with no significant down regulation of the metabolism.
Just like the results of the study Dr. Rudolf Liebel did, the contestants of The Biggest Loser did see a slower metabolism after the intervention, corroborating the set point theory. No doubt that the findings are disheartening to all who want to lose excess fat and keep it off permanently. However, I do believe that there is a better way. Moreover, I do believe that the “set-point” can be readjusted. The impression of the set point theory is that you can re-set the set point downward only i.e. a slower metabolism. I imagine the set point more like a thermostat. You can adjust a thermostat down…or up for your comfort. Why not the body’s set point?
I believe that most diet and exercise programs actually encourage the body to lower the metabolic rate. As a matter of fact, the body does so simply for self-preservation. Placing the body under extreme duress of the likes of The Biggest Loser, where the contestants are exercising 7 to 8 hours a day on a very low-calorie diet (1,000 calories a day or less), for over four months, the metabolism will shut down. It has to so the body can survive. Extreme diet and exercise programs will throw the hormonal system completely out of whack, and I imagine that it is almost impossible to get the body back to functioning in a normal sense again.
I do believe that you can turn up the set-point of the body to burn more calories for the same amount of exercise…and at the same time to decrease the appetite to prevent over-eating. All we have to do is send the proper signals to the body. The signals we want to send are:
- Build and maintain strength/muscle mass.
- Release fat from the fat stores more readily.
- Burn fat for fuel instead of sugar.
Too much exercise, especially aerobic exercise makes it more difficult for the body to build muscle. Additionally, the body learns how to burn less energy with consistent bouts of cardio exercise. That is one reason why the contestants of The Biggest Loser had a lower metabolic rate six years later. I know that they did some strength training as part of the plan, but they could not have trained very intensely considering the high volume of overall exercise they did.
A far more productive exercise program would be to cut the overall volume of exercise way down…even to the point of no aerobic exercise at all, and instead focus on two to three intense strength training sessions a week to encourage muscle growth. Over time the body will build more muscle, and it will tend to burn more calories even at rest.
Both appetite regulation and making the body more receptive to using fat for energy instead of glucose for energy has far more to do with the types of calories consumed than it does with how many calories are consumed. According the alternative hypothesis, high carbohydrate, low nutrient dense foods encourage overeating and fat storage, whereas low carbohydrate nutrient dense foods, like the Paleo way of eating, have the opposite effect. In large part, it does this by keeping the insulin response low, thus promoting the use of fat for fuel instead of glucose. This was a very different protocol than what Dr Liebel used (he had his dieter under 600 calories a day using only a meal replacement shake, which I have no doubt was very high in carbohydrates), and what the contestants had. The contestants had a lot of Franken foods such as jello, Kraft cheese and energy drinks and the like (see more here). This is a common practice for most dieters, and I believe that eating like this makes it much more difficult to keep weight off in a sustainable way.
To everybody who has tried to lose fat the conventional way but failed to maintain it, I say there is another way. All hope is not lost. Try an approach similar to what I outlined here and see what happens. You will lose fat. You will gain muscle. More importantly, you will not beat up your body, and it will be much easier to keep what gains you do make without feeling deprived.