Gaining Weight by Not Eating Enough??

By: Shelby Nolan


This isn’t likely, and I’ll tell you why. Weight change is determined by your energy intake and your energy expenditure. If you have a higher INTAKE than expenditure, meaning you are eating more and moving less, you will gain weight. If your EXPENDITURE is higher, meaning you move more and eat less, you will lose weight.


But this hasn’t always been the case for you, am I right?


You’ve dieted. You’ve exercised. But your weight stayed the same or even went up! (Weight gain doesn’t necessarily mean fat gain, which is detailed in another blog post at so check that out if you need a refresher!)


Let me shed some light on the matter. You may have heard of “starvation mode” or “survival mode,” in which the body holds onto fat even though you’re on a diet, and this evolutionary adaptation is supposed to protect you in times of scarcity. Hold onto your hats, because we are going on a scientific adventure.


There are absolutely adaptations that take place during calorie restriction (AKA eating less than you need), and these adaptations may affect your success in continued weight loss (which I’ll discuss further in another post), but first I want to reference the Minnesota Starvation Experiment. During WWII, researchers were trying to understand starvation and how to help those who had suffered during the war. The subjects were put on a grueling diet: 50% fewer calories than their bodies needed. They lost more than 25% of their weight. This, combined with any images you’ve seen requesting donations for a group of people suffering of famine who are so thin their bones are visible, will be enough to show you that a sustained calorie deficit (AKA eating less than you need) will most definitely result in weight loss. There is no starving person who is struggling to lose weight.

Now, what if you’re just starting on a new lifestyle? You’re eating right and exercising but nothing is happening. I don’t mean to be the bearer of bad news, so I won’t be. I’ll be the bearer of good news. The good news is your metabolism is more than likely not messed up. What is almost certainly happening is you aren’t tracking your calorie intake (AKA food) accurately.

In this study, obese participants reported both their energy intake (food) and expenditure (exercise). Their energy expenditure was overreported by 51% and their food intake was underreported by 47%.

It is a common propensity of folks trying to lose weight to assume they aren’t eating too much and they are burning if all off via intense exercise. (This can relate to the inaccuracy of fitness trackers’ display of calories expended, which I will discuss further in another post.) But you aren’t holding onto fat because you’re dieting. That’s for certain, so don’t blame “starvation mode” for not losing weight like you want to. It just means it’s time to take a closer look at your calorie balance.