Let’s now fast forward to the modern era, and look at this study published in the prestigious New England Journal of Medicine.

In this experiment, 18 obese and 23 non-obese subjects with a stable weight were recruited. They were fed a liquid diet of 45% carbohydrate, 40% fat, and 15% protein until the desired weight loss or weight gain was achieved.

One group targeted a 10% weight loss and the other group targeted a 10% weight gain. After weight gain, subjects were then returned to their initial weight, and then a further 10% or 20% weight loss was achieved.

The question they wanted to answer was what happened to TEE when weight was increased or decreased. This was achieved without a change in the composition of the diet. That is, the liquid diet was a constant ratio of carbohydrates, fats, and protein. The only variable was the total intake of this liquid diet. What happens to TEE when caloric intake is varied?

In other words, if we reduce or increase our Calories In, what happens to Calories Out? According to the conventional Caloric Reduction as Primary (CRaP) hypothesis, as Calories In go up or down, there should be not much change in the Calories Out.

What happened? In the 10% weight gain group, people increased their energy expenditure by almost 500 calories/day. Remember that one of the key assumptions of the CRaP theory is that in response to caloric change, TEE does not change. This is clearly NOT TRUE.

Instead of a simple calories in, calories out model where fat is deposited according to an excessive intake of calories, it appears that the body responds to excess calories by trying to burn them off!

Now let’s see what happens as the weight is returned to normal. Here, things start to get really interesting. As weight returns to normal, TEE returns to baseline. As we move into 10% and 20% weight loss, the body reduces TEE by about 300 or 400 calories per day.

So, as we begin to lose weight, the body responds to the weight loss by reducing TEE. This slows weight loss, and encourages weight regain despite full compliance with the diet. In other words, an increase in Calories In causes an increase in Calories Out. A decrease of Calories In causes a decrease in Calories Out. This is the body’s normal response. Weight loss will plateau, but not because you weren’t following the diet. Because that is the expected physiological response. It happens to everybody!

If you were trying to lose weight by eating less (Caloric Reduction as Primary), this is where you go, “WTF?!! OMG, That sucks! Where’s my frowny face emoji?”

Our body acts much more like a thermostat. That is, the body seems to have a certain Body Set Weight (BSW). Any attempts to increase above this BSW will result in our body trying to return to its original weight by increasing TEE (increasing metabolism to burn off the excess calories).

Any attempts to decrease below this BSW will result in our body trying to return to its original weight by decreasing TEE (decreasing metabolism to regain lost calories). No wonder it is so hard to keep the weight off! As we slow our metabolism, we must further and further reduce our caloric intake to maintain weight loss.

Here’s the misguided dietary technique of portion control or Caloric Restriction as Primary. We reduce our portion size but keep meal timing and composition the same. We reduce our calorie consumption from 2000 cal/day to 1,600 cal/day. Our weight may reduce, but then the body would respond by reducing TEE to about 1,600 cal/day. We might feel cold, tired, miserable, and hungry. If you have ever been on a diet — you probably know how that feels.

The worst part of it is that we don’t lose any further weight because we are eating less and burning less. Any slip in the diet, even to the previous normal 2,000 cal/day will result in weight regain. Discouragement sets in. We get tired of feeling so lousy so we go back to our regular diet. All the weight comes racing back with a little extra for good measure.

We feel that we have failed ourselves. We think that it is our fault. Our doctors, dietitians, and other medical professionals silently criticize us for ‘failing’. Others silently believe we have no ‘willpower’, and offer meaningless platitudes. Sound familiar? Yeah, I thought so.

But in truth, the failing was not ours. The portion control diet is virtually guaranteed to fail. It has been proven over and over in the last 100 years. The only reason we think that it works is because everybody — the doctors, the dietitians, the ‘scientists’, the media — have convinced us that it is all about calories. No, the failing is with our nutritional authorities.

Clearly, something is causing us to gain weight, but calories sure don’t look like the problem or the solution here. What is that problem? What is the etiology of obesity? What causes fat gain?