10 Symptoms of Undereating

With all the fearmongering about overeating, it’s easy to minimize the risk of not eating enough. Food is our body’s source of fuel, and undereating is dangerous. This blog post details 10 symptoms of undereating to help make sure you’re eating enough.

Given the fatphobic society we live in, there’s a ton of fear about overeating. Sometimes people do struggle with consistently eating significantly more than their body needs, which by the way has much more to do with things like backlash to restriction, trauma, food access, stress, and depression than it does about willpower. Because there is so much fearmongering about overeating, the risk of undereating gets minimized.

The way “healthy eating” is often taught is teaching people to eat as little as possible without keeling over. Of course, that is not actually healthy eating. Hopefully you are well familiar with my hierarchy of nutrition needs, where adequacy is the base of the pyramid. Because “weight management” and “healthy eating” have become synonymous, what most people think of as healthy is actually restrictive. I often ask new clients what they think a healthy day of eating looks like, and 9 times out of 10 they describe a pretty skimpy day of eating. What they think of as an appropriate amount of food is in fact barely enough for a small child.

Because energy needs vary from person to person, undereating looks different for everyone. There’s not a caloric amount that defines undereating. If you’re wondering if you might not be eating enough, here are 9 symptoms of undereating.

9 Symptoms of Undereating

Anxiety or irritable mood.

If you’ve experienced hanger, then you know what I mean! We all know how short term hunger can impact mood, but long term undereating can have a more significant impact than just getting snappy towards your partner when dinner is late to the table. An underfueled brain will struggle with regulating mood. Studies have shown higher levels of tension, anger, fatigue and confusion in people with higher levels of hunger. If you’ve been struggling with mood or feeling higher levels of anxiety, it may be that your brain needs more fuel, especially if you are dieting or struggling with disordered eating. For more on the relationship between anxiety and hunger, read this blog post.

You’re thinking about food all the time.

One of the ways our brain signals that it’s time to eat is by directing thoughts to food. Makes sense, huh? You might notice this when the clock ticks closer to lunchtime, and suddenly you’re having a harder time concentrating as your brain wanders to what might be served in the lunch cafeteria. Totally normal stuff! However, if thoughts of food consume your day, it’s likely a symptom of undereating.

A classic example of this is the Minnesota Starvation Study, where a group of physically and mentally healthy men were placed on a semi-starvation diet (although I will note it was an amount of calories that most people wouldn’t think of as starvation - higher than a lot of weight loss diets!). The men experienced significant physical and mental side effects, one of which was an obsession with food. They traded recipes and collected cookbooks, talked about food, and lost interest in school, sex, and hobbies, all because they were thinking about food all the time. While it’s possible your “foodie” interest might just be an interest, it can also be a symptom of undereating.

Low energy.

Food is our fuel. We don’t photosynthesize or take gasoline or use batteries. We eat food, break it down into smaller nutrients, namely amino acids, fatty acids, and glucose, and use those nutrients to fuel all our bodily processes - walking, talking, thinking, breathing, etc. So it makes sense that one symptom of undereating is low energy levels. If you’re tired all the time or struggling with low energy despite getting enough sleep, lack of food might be the reason.

Feel dizzy or lightheaded frequently.

When your body is running short on fuel, you may experience a low blood sugar, which is defined as a blood glucose less than 70 mg/dL. Usually when blood sugar drops, your body will tap into backup supplies of glucose that are stored in the liver. If you are chronically undereating, those backup supplies may be low and put you more at risk of a low blood sugar and the resulting dizzy and lightheaded feeling.

Constipation, severe bloating, or alternating diarrhea and constipation.

When you eat less food, there’s less bulk to keep things moving through the digestive tract, which can result in constipation. Also, when you eat, it triggers the waves of muscle movement that push food through the digestive tract, a process called peristalsis. I explain it to my clients as the drunk guy at a football game who gets the wave going if you’d like a fun visual for that one! When you go long times without eating, it doesn’t trigger those waves of muscle movement, keeping food stuck in the intestines longer. When food is in your digestive tract for a longer period of time, there’s more fermentation and gas. For some people with constipation, things can get backed up to the point where eventually pressure rapidly pushes things through, resulting in diarrhea.

Loss of menstrual cycle.

There are many causes of amenorrhea, but the most common is chronic undereating. Your body tightly regulates energy balance, and when you’re not eating enough, it will make changes to conserve energy. It saves energy for more vital activities (like, ya know, breathing, heart beating, that kinda stuff), and slows down non-essential areas, like your period/preparing for a pregnancy your body isn’t nourished enough to carry.

Binge eating.

While binge eating can occur for reasons other than restriction, the most common cause is undereating. I explain it to my clients using a pendulum analogy. Not eating enough pulls the pendulum back towards restriction, then when one little slip happens, the pendulum swings back in the other direction towards binge eating. While a binge can feel rally scary and out of control, it’s important to remember that it’s simply your body’s way of protecting you against starvation.

Wonky hunger and fullness cues.

Because we all know I love a good analogy, here’s another one for you! Imagine you have a friend who you decided to ghost. Eventually, they would get the picture and stop calling and texting you, right? The same thing happens with hunger cues. When you continuously ignore them, you can lose your hunger cues or only feel hunger when it’s extremely intense. This can feel confusing for people who are in eating disorder recovery, because why should you eat when you’re not hungry? The cool thing though is just like if you pick up the phone and call your friend back to reestablish a friendship, you can reestablish hunger cues by eating regularly, even if you aren’t hungry. This is where working with a dietitian can be helpful in creating a flexible plan for food.

Wonky fullness cues can also be a symptom of undereating. When someone isn’t eating enough, their stomach can feel very full quickly, either due to slowed stomach emptying (i.e. gastroparesis) or difficulty distinguishing bloating and indigestion from fullness.

Feeling cold all the time.

If you’re regularly feeling chilly or bundling up when other people are comfortable, it might be a symptom of undereating. Spending less energy on temperature regulation is another way the body conserves energy when it’s underfueled. Also, body fat helps regulate temperature, so if you’re under your body’s set point range, that could also be contributing.

Difficult with decision making or focus.

Did you know that your brain is the most metabolically active organ? In fact, the average persons brain accounts for 2% of their body weight, but consumes about 20% of your glucose supply. Since glucose is your brain’s primary source of fuel, as you can imagine it doesn’t work very well if it’s running low on energy from carbs If you’re regularly having a difficult time making decisions or a hard time focusing, it may be a symptom of undereating.

If any of these symptoms resonate with you, feel free to reach out! You may benefit from working with a dietitian to assess your intake and help you relearn how to fuel your body adequately throughout the day. We work with clients in our Columbia, SC office and virtually throughout the US, or we can connect you with an intuitive eating RD in your area. Learn more about our services here.