By Scott Abel
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The 10-Day Metabolic Slowdown, and the 25-Day Rebound
No study of the biology of weight-control and the ‘true’ understanding of metabolism would be complete without revisiting the topic of “metabolic damage” on several fronts.
In this post I want to look at a very interesting research study on metabolism and the effects of dieting, that was done at The University of Geneva. (You can look at the references for more details.) This study on diet and metabolism involved 3 groups of rats all eating the same quality of food. It is important to keep that distinction in mind as we proceed.
- Group 1: Were adult rats all eating normally
- Group 2: Were adult rats temporarily losing weight by eating less
- Group 3: Were younger rats who were “naturally” thinner and they weighed about as much as the rats from Group 2 after those rats had dieted and lost weight.
Let’s make a comparison to humans.
- If this study were done on humans then we would say that Group 1, the normal group, would be akin to a typical adult woman around the age of 35.
- Group 2, the “eat less to lose weight” group, would be this same demographic of women who are now going on a diet, for their wedding or for some high school reunion or whatever, and they are eating fewer calories and won’t stop until they get to their goal weight or goal dress size (or to fit into their “skinny jeans” from years ago, or something).
- Group 3, the naturally thin group, would be represented by those women who are naturally slender and fit into their skinny jeans their whole lives without really dieting to do so.
This makes for an interesting mix and comparison, doesn’t it?
For the first 10 days of the research the Group 2 “eat less” group of rats ate 50% less than usual, while the Group 1 “normal group” of rats continued to eat normally. So to translate this to human dieters, compare non-dieting adult women with women out there doing diets like the HCG diet, the Bernstein diet, and so many others that fit your basic “diet by calorie-restriction” recipe.
On the tenth day of the diet, Groups 1 and 3 kept eating normally. Group 2, the diet-by-caloric-restriction group, stopped the calorie-deprivation dieting and went back to eating normally as well.
This is when the really interesting stuff happened.
The research went on for 35 days. This means that the Group 1 rats ate normally for 35 days. The diet by calorie-restriction Group 2 rats ate less than normal for 10 days in a row, then were allowed to eat “normally” for the next 25 days. (This does not mean they ate what they wanted. It was controlled so they actually ate the same amount as Groups 1 and 3.) And the Group 3 naturally thinner group of rats ate normally as well for the duration of the study.
So, at the end of the 35 days, what do you think the results of this study were in regards to changes in bodyweight? Look at these results:
At the end of the 35 days the Group 2 “dieting rats” weighed the most AND they had the highest bodyfat percentage as well!
Even though Group 2 ate less than the other two groups of rats for 10 days, by day 35 they were SIGNIFICANTLY heavier than others.
Eating less for a sequence of time caused metabolic adjustments that led the Group 2 “dieting” rats to gain weight. This is what I refer to as “metabolic damage.”
Now, in place of rats, imagine these ladies I made comparisons to above. How many adult women do you know who go on special diets “just this once,” for some major event in their lives? The result is short-term weight-loss, followed by long-term weight gain and fat gain! Yet people still aren’t listening.
The researchers in this particular study concluded that eating less (as in a calorie-deprivation diet) is actually worse than doing nothing at all. Your body doesn’t know the difference between a temporary diet and starvation. Those are psychological distinctions, not physiological ones.
After a deprivation diet the body’s number one priority is restoring all the bodyfat it surrendered on the diet. It wants it back, ASAP. (After all, who knows when you’ll be starving again!?) Your body’s number two priority is to protect itself from this kind of starvation happening again, so the body increases weight and bodyfat mass as well in the post-diet “rebound” period.
Researchers have labeled this as “bodyfat supercompensation accumulation,” which your can think of as an off-shoot of what I called “metabolic damage” back in early 2003.
Other researchers actually argue that this bodyfat supercompensation accumulation effect of dieting can also be a trigger to future weight issues because of the potential Yo-Yo dieting that this effect triggers.
Read these next paragraphs carefully:
This cycle is all-too-common and recognizable. A woman diets for the normal, simple reasons outlined above. She loses weight for some event and everyone comments on how great she looks. Meanwhile, though, her body is now building up defenses against this weight-loss. It is slowing metabolism and slowing the rate it burns calories. To get her to eat more, hunger and appetite centers are lit up into overdrive.
Her short-term “successful” weight-loss turns into a long-term nightmare. She gains all the weight back, but she gains even more bodyfat as a percentage as well, all as outlined in the above rat research.
But here’s the difference between the human dieter and the rats:
Now the woman feels embarrassed and she feels shame. (Who likes looking in the mirror, and seeing yourself worse off than you were before?) The supposed solution? Well, she dieted once and lost all the weight, so she knows she can do it again. She just needs to do it “better and smarter this time.”
That is the lie so many dieters tell themselves. So she goes back on a diet and begins the cycle all over again. This is what the researchers mean when they say that the “bodyfat supercompensation accumulation phase” of diet rebound can be a trigger for future weight-gain and metabolic damage, because this phase of metabolic adaptation itself triggers a cycle of “Yo-Yo” dieting, because of psychological and emotional triggers.
Here is more sobering information about what happens next for the chronic dieter.
Researchers are now finding out something else I’ve been arguing for more than a decade now. When it comes to metabolic damage in the post-diet rebound period, this “bodyfat supercompensation accumulation phase” does not require someone to eat “a lot” in order to keep putting on bodyfat!
The fact is, that just by going to back to eating “normally,” like the dieting rats in this study, you can still gain a massive amount of weight quickly, even though these rats were only eating the same amount of food as the Group 1 and Group 3 control group rats for the last 25 days of the study.
As I outlined above, eating less also slows metabolism. When you subject a slowed, sluggish, or burned out metabolism to even “normal” amounts of food and exercise as a comparison control group, then these subjects will still gain more bodyfat as a result of the previous diet and its effect on the metabolic and hormonal and internal biochemical systems of the body.
The researchers in this excellent study illustrated that the Group 2 “dieting rats” were burning bodyfat 500% less efficiently, and that their metabolism was correspondingly slowed down by 15% by the end of the study.
Remember: the rats dieted only 10 days and the diet-rebound period was a follow up of only 25 days. But by the end, the Group 2 rats weighed the most!
Also as an important side note: when diet-by-calorie-deprivation produces this kind of response, the worst thing you could do at that point is “add cardio” to try to burn fat. To “attempt” to tap into the aerobic energy system when it is damaged this way is likely to further metabolic damage and hormonal disruption. That 15% slowed-down metabolism could easily become 20-25%. You may “feel better” psychologically by thinking you are “doing something about the problem,” but you are likely making things worse for yourself, not better.
Researchers around the globe are now piecing together the ‘damaging’ effects of prolonged and even short-term ongoing calorie-deprivation diets. While I categorized all these consequences under one umbrella I termed “metabolic damage,” researchers are now looking at very specific metabolic consequences such as the ones outlined above, often referred to as “metabolic dysregulation” in the research.
But researchers are also looking at negative hormonal and internal biochemical consequences of dieting as well. As I pointed out in my book, The Anti-Diet Approach to Weight-Loss and Weight-Control, the heaviest and fattest demographic population on the planet are those who report to belonging to the demographic of being “chronic dieters.”
What this research also illustrates is that the proper way to control weight is not via “quantity” of calorie intake, but rather through “quality” food choices, natural whole foods as often as possible.
About the Author
Scott Abel is a former professional bodybuilder and coach to over 400 fitness and bodybuilding champions at the National level and beyond. Learn more from his broad spectrum of work at www.scottabelfitness.com. You can also hear Scott on the 180D podcast. On April 6th, get three of his newly-released eBooks on Amazon for just 99 cents each. Click HERE.
Abel, Scott “The Anti-Diet Approach to Weight-Loss and Weight-Control”
Bailor, Jonathon “The Calorie Myth” 2014
Young, EA et al, “Hepatic Response to a Very-Low-Energy-Diet and Refeeding in Rats” American Journal of Clinical Nutrition, 1993 – (also in Pubmed PMID: 8503353)