One of the most well established phenomena in all of weight loss research is weight regain. It has been shown that between 80 and 95% of dieters regain their lost weight (see research HERE & HERE). It has also been shown that two thirds of these “weight re-gainers” actually end up fatter after the diet than before they started (see research HERE).
But why? Why does this compensatory weight re-gain happen? And, is there anything you can do about it?
*Just a note. If you don’t like to know the WHY behind things and just want to know WHAT to do, skip to the “actions to take” section.
The Law of Metabolic Compensation
The calorie zealots want you to believe your body is a rudimentary calculator that only engages in adding and subtracting. Eat too many calories and/or use too little, and you gain weight. Add in more food and subtract out any exercise, and you will gain weight.
These calorie counting fanatics are either unaware, or don’t want you to know about what we call the law of metabolic compensation. This law dictates that your metabolism is not like a calculator at all but more like a thermostat or see-saw. You eat less and exercise more to burn calories, and your body compensates by making you more hungry while at the same time decreasing the amount of calories you burn at rest (resting energy expenditure or REE).
This is no small thing. This metabolic compensatory effect is undisputed in research on weight loss and means the harder you push on one end of your metabolism, the harder and more forcibly it will push back in the other direction.
Big and Individualized Effects
We humans can be a bit dense at times and often forget this key fact: a solution that works in the short-term, but fails to work or makes things worse in the long run, is not a solution that works. At best it is a waste of time, and at worst it amplifies the problem further. Hence the stats on weight regain and fat overcompensation quoted above.
Low calorie dieting, on average, decreases the amount of calories you burn per day by about 300. But that is the average. For some, this effect is much larger, and for others it is less.
Just briefly I want to mention something for the more savvy readers out there. Many, who are well versed in metabolism, will immediately point out that if you lose weight, then of course you are going to be burning less calories because you have less body tissue. True. But what research shows, and my clinical experience validates, is that the reduced rate of metabolic output goes far beyond what would be predicted from loss of fat mass or muscle mass.
A person who weighed 180 pounds who diets down to 150 pounds burns significantly less energy than another person of the same height who also weighs 150 pounds who did not diet. Something about dieting causes an exaggerated slow down in metabolic rate that goes beyond what would be predicted based on tissue loss. And, as pointed out previously, this comes along with strong and unrelenting biological sensations to seek food. That is a recipe for compensatory weight regain.
Let me give you an example of this. A person decides to follow a low calorie diet. They determine that their resting metabolic rate is 2000 calories per day. They decide, according to conventional wisdom, to reduce their daily calorie intake by 500 calories per day. Now they are consuming 1500 calories per day. They remain compliant and in a few weeks have lost a few pounds.
But, the metabolism compensates. This person starts feeling hungry all the time. Their energy begins to suffer, and they feel cravings for sweet, salty, and fatty foods. This makes it harder for them to comply. But worse than that, depending on their individual response to the law of metabolic compensation, their metabolism has now put on the brakes, slowing their daily calorie burn rate by between 200 and 800 calories per day.
Now let’s say they are one of those people that has a very large metabolic compensation. So large that it equals or exceeds the 500 calorie deficit they were following. At this point not only will all progress stall, but the person may even start gaining weight. This is something the calorie zealots will never tell you, and if you don’t want to take my word for it, follow the links throughout this blog, or read the very nice free review article out of the International Journal of Obesity posted in the references.
The damage can last and some proof.
You may have first hand experience with this metabolic slowdown or witnessed it happen with a friend or a family member. What you may not be aware of is that this effect can last for long-periods after the diet is over, even after you have already gained back all the weight you lost or more!
Research shows the compensatory effects from dieting last for months and possibly years and may “damage” the metabolism over the long run.
As a clinician who works with weight loss and obesity, I can tell you with certainty that people can and do become weight loss resistant and can develop some degree of “metabolic damage”. Metabolic damage is a non-diagnostic term many in the weight loss industry use to describe a set of functional disturbances. These disturbances include severe metabolic compensations that result in a depressed metabolic rate, chronic fatigue, immune suppression, and multiple hormonal effects (i.e. suppressed thyroid function, adrenal stress maladaptation, and loss of libido and/or menses).
Research has shown this is NOT an imaginary issue. As far back as 1975, researchers published a study in the journal Lancet that looked at the issue of weight loss resistance. 29 women who claimed they could not lose weight were studied. The researchers, like many of us, assumed these women simply were not compliant and wanted to test their metabolism by sequestering them in a house and controlling all food and exercise they did. Each woman was put on a strict 1500 calorie a day diet.
At the end of the 3 week period most of the women ended up losing weight. However, 10 women did not lose any weight, and 1 of the women actually gained weight. This makes two points very clear. First, metabolism varies from person to person. Second, compensatory reactions can suppress the metabolism so much that even very low calorie diets are no longer effective even in the short-term.
3 Major Causes of Metabolic Slow-Down
The study in this area is fairly robust, and scientists have a pretty good handle on what might be happening. There are many potential issues here, but I am going to cover what appear to be the three major effects that are leading to this issue of weight loss resistance and weight gain. One of them is probably going to surprise you.
Loss of muscle mass
Research shows basal metabolic rate (BMR) accounts for over 2/3 of the calories burned at rest. Over 1/2 of BMR can be accounted for by the amount of muscle mass a person has. This means one of the best ways to offset the law of metabolic compensation is to do everything in your power to gain or at least maintain muscle.
A study published in the Journal of the American College of Nutrition in April 1999 showed this effect. This study looked at a group of obese individuals who were put on a very low calorie diet and assigned to one of two exercise regimes. One group did aerobic exercise (walking, biking, or jogging four times per week) while the second group did resistance training three times per week and no aerobic exercise.
At the end of the twelve-week study both groups lost weight, but the difference in the amount of muscle vs. fat loss was telling. The aerobic group lost 37 pounds over the course of the study. Ten of those pounds came from muscle. In contrast, the resistance-training group lost 32 pounds. None of the weight they lost came from muscle. When the resting metabolic rate of each group was calculated, the aerobic group was shown to be burning 210 fewer calories per day. The resistance-training group avoided this metabolic decline and instead was burning 63 more calories per day.
Hormonal changes: Leptin and Thyroid
Whether you reduce calories or lower carbs, one of the first things that occur in dieters is a beneficial change in either the amount and/or sensitivity of the hormone insulin. Insulin also acts as a hunger hormone, so this change, while beneficial, is one of the first and earliest changes resulting in metabolic compensation. This causes increased hunger. Other hormones are also impacted. Cortisol and ghrelin both will be elevated in pulses while dieting. This too causes increased hunger and cravings.
Along with the increased hunger and cravings comes the metabolic slow down. This is most impacted by the hormone leptin. Less insulin exposure to the fat cell and a shrinking fat cell means the metabolic hormone leptin is reduced. Low leptin means increased hunger. Low leptin also means decreased activity of the body’s two major metabolic engines, the thyroid and the adrenal glands. So as leptin decreases, your metabolism gets the signal to stop burning energy and to start consuming it.
Leptin is considered by many to be THE most important metabolic hormone as far as setting metabolic output and weight regain. If you want to keep your metabolic rate up, you have to make sure leptin levels don’t fall too fast. One way to overcome this appears to be a short period of overeating of between 1 and 3 days. This technique raises leptin levels and has also been shown to substantially raise a depressed metabolic rate. This effect varies substantially from person to person with some people showing no effect from the brief overfeeding and others seeing a jump in resting calorie burn of several hundred calories per day.
Now for the big surprise cause. There is another set of signaling molecules that have a huge impact on metabolic compensations during dieting. These compounds are present in your fat cells, and when fat is burned, they are released in significant concentrations. The shocking thing about these compounds is they did not come from your body. They are man made chemicals that you eat, put on your skin, drink in your water, and inhale through the air.
POPS stand for Persistent Organic Pollutants and up until very recently no one understood how these compounds were involved in weight loss resistance. Here is how it works:
- POPs are fat soluble and so concentrate in animal fat, including humans. You can almost see this as a protective mechanism. If the POPS are in your fat cells, then they can’t do damage. So when they get in your body, you store them away in fat.
- When you lose fat, they are released in significant amounts and can do damage and slow the metabolism.
- POPs primarily impact the thyroid gland by decreasing its ability to make thyroid hormone, disrupting thyroid hormones once they are made, and causing thyroid hormones to be removed from the body faster. If your metabolism is a large jumbo jetliner, the thyroid gland is one of the engines. POPs appear to work in part by blowing out the thyroid engine.
- In other words, POPs shut down thyroid function and drastically suppress metabolic function (for more on this read the review article in the reference section).
And if you think this effect is small, it may surprise you to know these POPs have a greater impact on metabolic rate than the all mighty hormone leptin. In other words, this is a very BIG deal.
Actions to Take
- When you go on a diet set your protein intake higher. Studies have shown that a higher protein diet, one that exceeds the RDA of .8g/kg body weight, helps offset the decline in metabolic rate that occurs with dieting. At Metabolic Effect, we set the protein level to 40% of total calories during fat reducing stages (i.e. 30:40:30 carbs:protein:fat). Another way to look at this is to make sure you are getting at least 1g of protein per pound of body weight (if you want to try to gain muscle) or 1g per pound of muscle mass (if you are trying to just maintain muscle).
- Eating a diet that has a lower glycemic load has also been shown to reduce the amount of muscle lost and at the same time increase the amount of fat lost while dieting. This means getting most of your carbohydrate intake from non-starchy vegetables, low sugar fruits and “wet carbs” like oats and beans versus breads and pasta.
- While diet is the most important aspect of achieving fat loss, increasing physical output after the weight is lost is essential and makes up some of the calorie deficit created by the slowed metabolism. This exercise should be something that does not stimulate appetite and can easily be incorporated into any lifestyle. We suggest you start with leisure walking and shoot for 1-2 hours daily (2.5-5miles or 5K to 10K steps).
- Cycle the diet in a way that has periods of reduced energy intake and periods of increased energy intake. This helps offset the leptin decline that occurs with dieting. There is individual variation with this, but for those who respond well, a day or a few days of overeating can set the metabolic rate back to a higher level. This cycling approach may be more effective for fat loss than the traditional approach
- Incorporating fish oil into the diet while losing can reduce the metabolic decline due to its positive impact on leptin signaling and hypothalamic sensitivity to other hormones. We prefer krill oil over fish oil at 1-3g per day, or regular fish oil at 6g-12g per day.
- Curcumin may be another agent that has applicability in this regard since it also has similar effects on brain and whole body inflammatory signals and leptin which can drive metabolic resistance and play a role in weight rebound. It also may play a role in protecting the body from the effect of POPs due to its effect on NF-kappaB.
- This last one is going to really bother the primal crowd, but the number one way to avoid POPs is to avoid high fat animal products. This means that a lower carb and higher fat diet may not be the best option as a fat loss diet. Making non-starchy vegetables and lean protein sources the priority may be best to deal with the POP effect above. If you have been doing well on a low carb high fat diet, don’t stop, just realize that this POP issue may become an issue in slowing the rate of your weight loss or be a factor in weight regain. If this has been something you deal with, you may want to try something closer to a 30:40:30 diet.
- Lipase inhibitors can play a role. These are foods that have action in decreasing the digestion of fats so they move out of the body instead of getting absorbed. Since the digestive tract is the major place where POPs are both removed from the body and taken into the body, doing what is possible to NOT allow fat soluble compounds reentry is important. Some common lipase inhibitors include green tea, oolong tea, mate tea, and ginger root.
- Finally, increasing the livers ability to detoxify and remove POPs is key. Dandelion root, milk thistle, alpha lipoic acid, and vitamin C play a role here.