Newsflash: Your food restriction is making you fatter.
Our weight is as heritable as our height. Our weight has a genetic set range which can only change in one way: to widen to increase fat storage.
What causes an increase in our fat storage capacity? Starvation.
The evolutionary reason for this is that we've been adapted to avoid starvation. For millions of years our ancestors survived by evolving the genetic ability to store large amounts of fat.
This is why every kind of diet increases the body weight set range. The hypothalamus, thinking the body is in famine due to low caloric intake, will store more fat in the body to prepare for the next possible famine.
Epigenetic tuning of the genes pushes up a person's weight set range. Large population studies prove that dieting makes people fatter; today the average person weighs 30 pounds more than 60 years ago, when fewer people dieted.
Those with genes that cause obesity have a genetic lineage of adapting to famine very well. Their bodies have a great capacity to naturally store a lot of fat.
People who restrict food and keep themselves underweight are pushing up their genetic weight set range. Their bodies are becoming more capable of storing fat than if they had never become underweight.
Binging and purging also increase a person's weight
Purging food (by restricting food, exercising, or vomiting) only pushes up the body weight set range. Besides that, purging food also just sets the stage up for the next binge.
It was Garner and Garfinkel's Handbook (1985) that showed how over time, purging and binging increase a person's weight. The reason for this is likely the same as why restricting food intake will increase someone's weight range. The hypothalamus is increasing one's weight set range, storing fat in response to thinking it's in famine. (The hypothalamus is the part of the brain which reads leptin levels and regulates food intake and energy expenditure, maintaining homeostasis.)
Every fad diet makes you fatter
According to Dr. Jennifer Gaudiani's Sick Enough, almost every study shows that those who restrict calories on a diet will temporarily lose weight, then gain all the weight back plus more weight.
Conclusion: Eat more now to stop from becoming more fat in the future.
Staying underweight causes one to increase their capacity to store fat.
The longer an underweight person spends in starvation, the more their body will increase its fat storage capacity. The sooner an anorexic restores to their natural weight, the sooner they can halt the epigenetic alterations to their genes which are pushing up their capacity to store fat.
For those who are anorexic and trying to recover: just because you may now have the ABILITY to store more fat than before you got anorexia, it doesn’t mean you WILL store more fat.
Many anorexics don't want to be fatter. The only way to halt this process of fattening is for them to eat more fat and calories now to tell their bodies that they're no longer in a famine.
Much of the above research is paraphrased from Dr. Shan Guisinger's writings.
Restricting food is mentally more stressful than not restricting
Restricting food can be more stressful than just eating it. Letting go trying to restrict your food - and just eating more food and enjoying the flavor - can make you feel less stressed out.
No matter what the amount of stress you have, know that restricting food feels more stressful than just eating it. Restricting by itself is such a stressful act.
When you relax and eat high-calorie food, you will feel better. Your body will have more energy
Disclaimer: I am not saying that it is bad to be fat. I share this information because it's useful to the many people with eating disorders who restrict food in an attempt to decrease their natural fat stores. It turns out, they are doing the opposite by restricting food.