While figuring out your exact calorie count may seem difficult, if not impossible (due to numerous factors), you would think it would be easy to see when you’re overeating vs. undereating. Unfortunately, that’s not always the case. Especially with regular dieting or controlling food intake, people can get detached from their own hunger cues. This can make it difficult to accurately assess your body’s needs.

Symptoms of Overeating vs. Undereating

Overeating vs. undereating can both have negative impacts on your health and on reaching your goals. Some of the most common signs of each include:

Overeating

• Acid reflux
• Bloating
• Gas
• Heartburn
• Nausea
• Stomach pain
• Feeling tired or sluggish
• Weight gain
• Decreased physical performance
• Disordered eating

Undereating

• Insomnia or frequent waking at night
• Lack of appetite
• Nagging injuries or slow recovery
• Lowered immunity, so you get sick more often
• Malnutrition
• Anemia
• Obsession with counting calories, macros, or types of food
• Intense or insatiable hunger
• Low energy levels, fatigue, and depression
• No change in body composition or weight, despite efforts to lose weight
• Decreased physical performance
• Disordered eating
• Hair loss

In addition, both overeating and undereating can impact hormone levels, which affect bodily functions, overall health, and well-being.

For instance, overeating can lead to:

• Increased cortisol levels, which can increase cravings for foods that are high in sugar, fat, or salt, which can lead to eating even more.
• Disruptions in ghrelin and leptin balance. Ghrelin normally increases hunger signals, while leptin indicates when the body is full after eating. Overeating regularly can disrupt this balance, leading some people to continue eating even after they’re full, which can again contribute to eating more.

On the other hand, undereating can affect:

• Hormones that regulate the metabolism as the body does its best to conserve energy. This can affect bone and muscle health as the body can take needed nutrients from those tissues. This loss can increase the risk of osteoporosis and other issues.
• Thyroid levels, which can cause you to feel cold, dry out the skin, or lead to constipation.
• Stress hormones, including cortisol, growth hormone, and noradrenaline, which can lead to sleep disturbances, depression, and anxiety. It can also cause the heart rate and breathing to race.
• Reproductive hormones, which can reduce sex drive and negatively affect fertility in both men and women, as well as lead to irregular or absent menstrual cycles in women.

Why Do People Overeat?

Overeating, eating past fullness, or eating when we’re not really hungry is common. For instance, many people find they overeat at parties or family gatherings or while stressed. But if overeating becomes habitual, it can lead to weight gain and perhaps disordered eating over time as it overrides the natural signals from ghrelin and leptin.

Other factors that can lead to overeating include how fast you eat. For example, if you eat quickly, you can eat more than you need before your body has a chance to register that you’re full.

What you eat also plays a factor. For example, many processed foods are high in calories and sugars despite their small serving size. That makes them easy to overeat.

What you’re doing as you eat also impacts how much you eat. If you eat while driving, working, or otherwise distracted, you may find you eat way more than you intended.

Other reasons people overeat include:

• Emotional eating, when you’re stressed, overwhelmed, in a bad mood, sad, burnt out, or just tired or bored. Eating is an easy way to release endorphins that help lift mood. Unfortunately, eating to feel good rather than because you’re hungry makes you more likely to overeat.
• Preferred food choices. It can be difficult to say no to your mom’s lasagna, homemade bread, or cookies, or childhood favorites like French fries, chips and dip, sweet cereals, pizza, chocolate and candies, or ice cream. While no foods need to be off-limits, it can help to dish out a single serving and then put the rest out of sight to limit temptation. Or skip foods that trigger overeating as you learn to better understand your body’s food cues.
• Highly processed foods loaded with sugar and fat are designed to encourage you to eat for pleasure rather than for fuel. There’s a reason one potato chip brand dares you to try to eat just one.
• Evenings or during the afternoon “slump” when you may want a bit of an energy boost.
• Family-style or buffet-style restaurants or parties where it’s easy to load your plate with large portions.
• Finally, certain medications and medical conditions can contribute to overeating.

Again, overeating from time to time is only natural. The physical effects, such as feeling sluggish or having heartburn or a tummy ache, will typically go away within a few hours. Drinking plenty of water and doing some gentle exercises can often help you feel better faster.

Noticing when you’ve overeaten can also provide clues as to why you’re eating more, so you can put a plan in place to prevent overeating in the future.

Why Do People Undereat?

Perhaps the biggest reason people undereat is to lose weight. After all, that’s the usual advice: To lose weight, you need to eat less. So, you lower calories or follow a restrictive diet on purpose to drop some pounds or improve health.

Sometimes, people follow restrictive diets without realizing it due to inappropriate nutritional advice (often from a friend or influencer) or a misinterpretation of sound advice. Others may unknowingly eat too little or believe they’re following a healthy diet.

Some folks just have fast metabolisms or extremely active lifestyles and find it difficult to eat enough to keep up with their body’s demands.

Sadly, many people lack access to the food they need to sustain a healthy lifestyle. Up to 12.9% of people worldwide are undernourished. While this is more common in developing countries, hunger occurs everywhere, especially in food deserts.

Stress is another reason people undereat or forget to eat, especially after experiencing trauma or grief, such as the loss of a loved one. As well, mental health conditions, including depression, can affect how much and how well you eat.

There are also more serious conditions that cause people to undereat, including eating disorders like:

• Orthorexia, an unhealthy obsession with healthy eating
• Anorexia nervosa, an unhealthy low body weight and intense fear of weight gain combined with body dysmorphia (i.e., not seeing the body as it truly is)
• Bulimia with episodes of bingeing often followed by purging either by throwing up or exercising excessively
• Avoidant/restrictive food intake disorder, which includes extremely limited eating or avoiding certain foods or entire food groups due to their color, texture, taste, or smell (rather than because of a fear of weight gain)

For people who are overcoming an eating disorder, it’s important to reach out for professional help to improve your relationship with food.

How to Know If You’re Overeating vs. Undereating

Because both overeating and undereating can make weight loss more challenging, it’s easy to get confused. The most important thing to do is listen to your own body.

For example, do you feel uncomfortable after eating a meal, especially if you ate quickly or while distracted? Then, you might be overeating.

If you find you’re fatigued and aren’t sleeping well, or that you’re constantly hungry, you may not be getting enough calories.

In addition, if you’ve drastically cut back calories yet your body composition is staying the same, counterintuitively, you may need to eat more to rebuild your metabolism. To reverse the trend, you may choose to eat maintenance calories for your current weight as your metabolism improves, or you may choose a “reverse diet” as a caloric surplus may increase basal metabolic rate and help you start making progress again.

Finding a Healthy Balance

Both overeating and undereating can lead to health risks, including unwanted weight gain and disruption of the delicate hormonal balance that regulates hunger. It can also lead to nutrient deficiencies, especially if you’re overeating (or only have access to) highly processed foods. So, whether you’re overeating vs. undereating, the key is to find a balance that aligns with your body’s needs, activity levels, and goals.

For people who overeat, you may need to learn to eat for energy and nourishment rather than just for pleasure. It can help to practice self-care and engage in food-free fun activities that boost your energy and mood. That could include a walk in nature, dancing, playing a game, laughing with friends and family, or whatever makes you feel good or brings you joy.

You may also need to work with your healthcare provider to see if a medical condition or any of the medications you are on are contributing to the problem.

For people who undereat, slowly increase caloric intake and ensure you’re eating a balanced diet rich in macronutrients and micronutrients. A nutritionist or dietitian can help you develop a personalized eating plan to increase energy levels and help you reach healthy goals.

For both people who overeat and undereat, it’s important to:

• Eat a variety of foods to provide a range of nutrients
• Avoid extreme diets or eating patterns that can lead to disordered eating
• Adjust your food intake based on your activity levels
• Learn to listen to your body and recognize hunger and fullness cues.

Eating Mindfully to Help Overcome Undereating vs. Overeating

One powerful way to become more in tune with your body’s needs is to eat mindfully. Focus on why and how you’re eating rather than just what you’re eating, which allows you to make more deliberate food choices to suit your body, goals, and values.

Slow down, enjoy, and appreciate the food, including the vibrant colors, smells, textures, and flavors. You may find this provides more satisfaction and gratitude for the food that nourishes your body. Over time, this can help curb cravings as you better understand your body’s cues and how the food makes you feel. You may even find foods you used to overeat don’t taste nearly as good as you once believed.

Eating mindfully can also help regulate eating patterns, improve digestive health, and help you better manage your weight whether your goal is to lose weight, gain weight, or maintain your current weight.

This approach can also foster a more positive, non-judgmental attitude toward food and yourself as you replace rigid rules around eating with greater curiosity, exploration, and attention.