I wanted to point out an article that looks at the compensations with low-calorie diets in detail. It is free full-text, and here is a portion from the abstract:
“For the first time we show that in free-living conditions, CR results in a metabolic adaptation and a behavioral adaptation with decreased physical activity levels.”
This is something that doesn’t get mentioned much with low-calorie diets.
So here are three things that will happen when you eat a 1,000 calorie diet (represented by LCD (low-calorie diet) in this study):
- Your metabolic rate will slow.
The paper discusses this in some detail. (There was no real slowing in the CR+EX group though. In this group, it was a relatively minor calorie restriction of 12.5%, combined with an activity increase of 12.5%.)
- You will lose both fat mass and fat-free mass.
- You will move less.
It doesn’t seem like calorie restriction goes along with the “Let’s Move” campaign by Michelle Obama!
So here’s a question: how is moving less on a daily basis healthy? It’s not. Yes physical activity fell in all groups except those who were required to move via their study group (CR + EX). And this decreased movement was a direct result of calorie restriction!
To me, this study shows that giving a 1,000 calorie a day diet to a sedentary person is a recipe for disaster. They will end up with a lowered metabolic rate (independent of lean mass), loss of lean mass, and they will actually move less.
So why is this becoming the de facto option in mainstream diet books??