We live in a society where it has been drilled into our brains that the best way to achieve our dream body is with fewer calories and not more. But why is nobody talking about the dangers of severe calorie restriction when there are so many people doing it? And if it worked, why are millions of people in the U.S. still spending millions of dollars on different diets to find their answer even after calorie restriction? We recognize that many of you reading this love to exercise — and you may be part of a group of people who are at risk for underfeeding, since calories may be restricted paired with a high energy output. Read on to see if you are experiencing any of the symptoms that can occur from underfeeding and how to remedy it in a healthful way.

The signs and symptoms of undereating

Your weight is not budging

Probably the most frustrating part of chronic underfeeding is when weight loss is just not happening and, in some cases, you even start to gain. This can happen specifically for those that have been on a low-calorie diet for a long time or have been over-exercising. You probably have heard some people say that eating too few calories puts you in so-called “starvation mode.” Welp, they may be right. Eating too little activates the anti-starvation system, which helps your body hold onto fat whenever possible because it sees nutrition being scarce and does not want you to… well, starve.

It is a known fact that when you start losing weight, your metabolism slows because your body is getting smaller and smaller bodies burn fewer calories. But it turns out that many people experience an additional metabolic hit not directly related to being in a smaller body. In fact, the number of calories you burn during the day can drop by as much as 40 percent, which in turn may not help you lose weight, but also gain it! Another symptom that can decrease your chances of losing weight is decreased muscle mass from protein malnutrition, which can decrease overall metabolism and increase hunger hormones, causing you want to eat more post-underfeeding.

Your energy levels are tanking

Probably the first sign of underfeeding for most people is fatigue. Calories are our source of fuel and without them, our blood sugar levels can tank. So, the energy you once felt in spin class will definitely start to decrease even if you have been going consistently.

You may be more like to snap at your co-worker or spouse (i.e. you are hangry)

Serotonin is the brain chemical linked to both mood and appetite and when glucose levels drop in our bodies, our brains are not immune to that either. Serotonin levels drop and there is also a level in self-regulation. So, someone may need to get out of your way until you get lunch!

You often feel very thirsty

Chronic underfeeding can mean you are not getting enough electrolytes and to top that off with sweating in your daily workouts, you could be lacking these highly important electrolytes which help hydration stay regulated in the body.

Your hair, nails and skin look drab and just are not growing

This is mainly due to protein malnutrition. Proteins are the building blocks (i.e. amino acids) that make up your hair, nails and even skin.

All you think about is food, 24/7

Probably the most well-known study out on starvation showed that those with restricted calorie intake think about food all the time. This can range from just excitement for your next meal to a completely debilitating feeling that takes over your existence to the point that those with eating disorders can experience.

Okay, so how many calories do you need?

Finding out the exact amount of calories you need can be very difficult, but there are some simple strategies to find estimates of your calorie needs based on your height, weight, age and activity level. Dietitians and medical professionals use the Mifflin St. Jeor equation as the gold standard to determine how many calories you need at rest. From there, you can use an activity factor to determine estimated total needs.

For Men

Here’s how it looks in an equation:
(10 x weight (kg)) + (6.25 x height (cm)) – (5 x age (years) + 5)

For Women

Here’s how it looks in an equation:
(10 x weight (kg)) + (6.25 x height (cm)) – (5 x age (years) -161)

This determines what amount (your BMR) you do not want your calorie needs to go below.

Then, if you want to add in activity, you would multiply your BMR by an activity factor.

Basic Activity Factor

1.2: If you are sedentary (little or no exercise) = BMR x 1.2

1.375: If you are lightly active (light exercise/sports 1-3 days/week) = BMR x 1.375

1.55: If you are moderately active (moderate exercise/sports 3-5 days/week) = BMR x 1.55

1.725: If you are very active (hard exercise/sports 6-7 days a week) = BMR x 1.725

1.9: If you are extra active (very hard exercise/sports & physical job or 2x training) = BMR x 1.9

This would give you a sweet spot amount of calories to start with if you want to get to a maintenance level of calories. Applications that allow you to log your food are also a great tool to assess calorie intake and compare.

So, if you have been on a low-calorie diet, exercising like a fiend, started the Whole30 with a friend or anything else that may threaten your calorie intake, we suggest listening to your body cues and making sure you don’t go too far. Work with medical professionals who can guide you and make sure you are eating in a healthy way to meet your goals.