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13 Important Signs That Indicate You Are Not Eating Enough

Whether it is due to illness, stress, any traumatic event, fad dieting, or because of a busy schedule, skipping meals, or not eating enough is seen in many of us. Just like overeating, under-eating, or not eating enough could have lots of negative impact on our mental and physical health. Apart from the obvious symptom of weight loss, many other signs indicate that you are under-eating. To find out some of the important signs your body says you are not eating enough, read the following array of the article.

13 Important Signs That Indicate You Are Not Eating Enough

13 Important Signs That Indicate You Are Not Eating Enough

Some people do not eat enough intentionally, usually as a result of adhering to restrictive diets or following specific health trends. However, these diets and health trends can contain inappropriate nutritional advice that might lead to under-eating. In other cases, you might not eat enough because of an eating disorder or just without realizing that you are undereating.

At times, people having an abnormally high metabolism of the body or high levels of physical activity, do not eat enough for keeping up the demands of their body.

Sometimes people do not eat enough because of stress, especially after experiencing or going through a traumatic event in their life. People might also under eat because of anxiety, depression, or other mental health issues.

However, poverty can also be one more reason why someone might be undereating. Worldwide, just below 800 million people do not have enough food to sustain a healthy lifestyle because of their financial condition.(1) This is seen especially in developing countries, where 12.9% of the total population is undernourished.

Some of the important signs that say you are not eating enough include, feeling tired or having low energy, hair loss, getting ill frequently, or skin problems. Let us take a look at these signs in a better way.

Low Levels Of Energy:

Units of energy that our body uses to function are known as Calories. When someone does not eat enough calories, they are likely to feel tired most of the time.

Resting Metabolic Rate is the number of calories required for basic functions within 24 hours. Most individuals have a resting metabolic rate higher than 1,000 calories per day. It must be noted that by adding physical activity, your daily needs of resting metabolic rate would increase by another 1,000 calories or more.

Restricting calorie intake to fewer than 1, 000 calories per day can slow down the rate of metabolism in your body and can cause fatigue since you are not consuming enough calories for supporting even the basic functions of your body that keep you alive.

Not eating enough has especially been linked to low energy levels in elderly people, whose food intake might reduce due to reduced appetite.(2)

Studies in female athletes have shown that fatigue might occur when there is a very low intake of calories to support a high level of physical activity. This seems to be most common in sports like gymnastics and figure skating that emphasizes thinness.(3, 4)

You might even get tired or have very low energy for light physical activities, such as walking or climbing stairs, if your calorie intake is below your daily needs.

Lower levels of energy can adversely impact your physical activity performances and overall fitness. In a review of 2013, researchers have found that people who have an eating disorder consumed fewer calories, which ultimately negatively impacted their physical fitness and sports performance.(5)

Frequent Or Constant Hunger:

One of the most important signs that say you are not eating enough is you are having frequent or constant hunger. Studies have confirmed that appetite and food cravings increase when there is a drastic calorie restriction because of changes in levels of hormones that are responsible to control hunger and fullness.

A 3-month study has followed mice who were fed with a diet that contained 40% fewer calories than normal. It was found from the study that the levels of appetite-suppressing hormones like IGF-1 and leptin reduced in mice and their hunger signals increased significantly.(6)

In humans too, calorie restriction might result in hunger and food cravings in both, overweight as well as normal-weight individuals.

In one study of 58 adults, it was found that consuming a 40% calorie-restricted diet had increased the levels of hunger by about 18%.(7)

Apart from this, it has been found that lower intake of calories has been linked to increased production of a stress hormone, called Cortisol, which has been linked to hunger and increased fat in the belly.(8, 9)

You must note that if your calorie intake drops excessively, your body would start sending signals that drive you to eat to avoid potential starvation.

Getting Ill More Often:

Are you getting ill more often? If yes, then you might not be eating enough. Yes, getting ill more often is one of the important signs your body says that you are not eating enough.

Not eating enough or undereating can lead to an imbalanced diet. This means that your body does not receive enough specific nutrients for maintaining a healthy immune system and fight against illnesses. This can also mean that illnesses like the common cold would last longer than usual.

For people already having a weakened immune system like those of young children or elderly people, it is essential to maintain a healthful nutritional intake regularly.

In a study, researchers have found that providing people above 65 years with nutritional supplements has resulted in significant improvements in the proper functioning of their body’s immune system.(10)


Infrequent bowel movements might be associated with inadequate calorie intake. This is because consuming very little food would result in less waste in the digestive tract of a person and thus would cause infrequent bowel movements or constipation.

Constipation is generally described as having three or fewer bowel movements in a week or having hard and small stools that are hard to pass. This is quite common in elderly people and can get worse by poor diet.

A small study that observed 18 older adults has found that constipation occurred most often in people who did not take enough calories. This was true even if they took plenty of fiber that is considered the most important factor for the proper functioning of the bowel.(11)

Dieting and consuming too little food might also result in constipation in young people because of a slowed metabolic rate.

In a study of 301 college-aged women, it was found that the strictest dieters were most likely to have constipation and some other digestive issues.(12)

So, if you are having problems with constipation too often, then it might be because you are not eating enough. Try to increase your calorie intake and see if you experience improvements in your symptoms.

Hair Loss:

Losing hair could be distressing. It is quite normal to lose several strands of hair regularly. But, if you are noticing an increased amount of hair is falling off, it might be a sign that you are not eating enough.

A lot of nutrients are required for maintaining a normal and healthy growth of hair. Inadequate intake of calories, biotin, protein, iron, and other nutrients is a common cause of hair loss.

When we do not take enough calories and primary nutrients, our body would prioritize the health of our brain, heart, and other organs over hair growth.

Feeling Cold All Time:

If you are constantly feeling cold, then you might not be eating enough food. Your body requires burning a specific number of calories for creating heat and maintaining a healthy and comfortable body temperature.

Even mild restriction of calories has been shown to lower core body temperature. In a 6-year controlled study that took 72 middle-aged adults, who consumed an average of 1769 calories every day, it has been shown that they had significantly lower body temperature than the group of people who consumed around 2,300 to 2, 900 calories, irrespective of physical activity.(13)

In another analysis of the same study, it was shown that the calories-restricted group had experienced a reduction in the levels of T3 thyroid hormone, while the other groups did not. T3 thyroid hormone is a hormone that aids in maintaining body temperature, among other functions.(14)

In one more study that observed 15 obese women, it was found that T3 levels reduced by as much as 66% during an 8-week period when the participants consumed only 400 calories per day.(15)

Overall, it can be concluded that the more severely you slash calories from your diet, the colder you are likely to feel.

Sleep Problems:

If you are suffering from sleep problems, there might be a chance that you are not eating enough. It has been found from dozens of studies that sleep deprivation is known to result in insulin resistance and weight gain.(16)

Though overeating might cause difficulty falling asleep, it also appears that strict dieting or not eating enough can result in various sleep problems.

Animal and human research has shown that starvation-level calorie restriction causes sleep interruptions and also a reduction in slow-wave sleep or deep sleep.

In a study of 381 college students, it was shown that restrictive diets and other eating problems were directly linked with low mood and poor sleep quality.(17)

In one more small study that took 10 young women, it was found that 4 weeks of dieting resulting in a greater difficulty in women to fall asleep and a decrease in the amount of time they spent in a deep sleep.(18)

So, keep a note that if you are feeling hard to fall asleep or waking up hungry then you might be not eating enough.

Impaired Growth In Young People:

Good nutrition is important for proper development in young people. Not eating enough or undereating can result in nutritional imbalances that impair specific aspects of development, like healthy bone growth.

Proper nutrition is vital during puberty and is essential to allow your bones to grow and strengthen. Without this, a person might permanently remain weaker or smaller than their peers.

Skin Issues:

Skin issues are another sign that says that someone might not be eating enough. If your body does not get a sufficient amount of nutrients like Vitamin E, it can cause various skin problems. A person’s skin might become more easily damaged by UV exposure or inflammation, without enough Vitamin E. Few other vitamins required for maintaining healthy skin include, vitamin B-3 and niacin.


In a large study that took more than 2, 500 Australian teens, it was found that 62% of those who were classified as “extreme dieters” reported an increased level of anxiety and depression.(19) Anxiety is also reported in overweight people who consume extremely low-calorie diets.

In a controlled study of 67 obese people who consumed either 400 calories or 800 calories every day for 1-3 months, roughly around 20% of people in both groups had reported an increased level of anxiety.(20)

For minimizing anxiety while trying for weight loss, make sure that you are eating enough calories and consuming a healthy diet that includes plenty of fatty acids for ensuring that you are getting enough Omega-3 fatty acids, which might help in reducing anxiety.


Depression is a severely complex mental health condition that can be caused due to several causes. It is always not possible to find out what is causing depression in a person, and the condition is not necessarily a sign of malnutrition. But, recent evidence suggests that there might be a link between poor or improper nutrition and depression.

In one study of people who were pregnant, it was found that symptoms of depression were linked with lower intakes of omega-3 fatty acid.(21)

In one more study that used data from 31, 424 adults, it was found that those with depression had lower levels of Vitamin D than others.(22)


One of the important signs your body says you are not eating enough is irritability.

One interesting fact is that irritability was one of the several issues that were experienced by young men who underwent calorie restriction as a part of the Minnesota Starvation Experiment during the time of World War II. These men were found to develop moodiness and other symptoms while consuming an average of 1, 800 calories per day, which was known to be classified as “semi-starvation” for their own calorie requirements. Of course, your own needs of calories might be lower.

A recent study of 413 college and high school students has found that irritability was linked with dieting and restrictive eating patterns.(23)

So, for keeping your mood high and avoid irritability, make sure that you are eating enough and not restricting your calorie-intake.

Inability To Get Pregnant:

We must let you know about one of the most important signs your body says you are not eating enough, and this is your inability to get pregnant. Undereating or not eating enough might interfere with a woman’s ability to get pregnant.

The pituitary gland and hypothalamus located in our brain work together for maintaining hormonal balance, which also includes our reproductive health.

The hypothalamus receives signals from the body that let it know when the levels of hormone are required to be adjusted. Based on these signals, the hypothalamus produces hormones that are known to either stimulate or inhibit the production of hormones like estrogen, progesterone, and other hormones by the pituitary gland.

Research has shown that this particular complex system is highly sensitive to changes in the intake of calories and weight.(24)

When your calorie intake and the fat percentage of your body drop extremely low, signals might become impaired, thus resulting in changes in the amount of hormones that are released.

Pregnancy cannot take place without the proper balance of reproductive hormones. Hypothalamic amenorrhea is the first sign of this issue. Hypothalamic amenorrhea is a condition when women might not be having their menstrual period for three months or longer.

In an older study, it was found that when 36 underweight women having amenorrhea or infertility related to calorie restriction increased their intake of calories and achieved an ideal body weight, 90% of them began menstruating and 73% of them became pregnant.(25)

So, if you are trying to conceive, be sure that you are consuming a well-balanced and adequate-calorie diet to ensure proper hormonal function and have a healthy pregnancy.

Final Words:

Now we know that although overeating can increase your chances of developing health issues, under-eating or not eating enough can also be harmful and result in various unwanted signs and symptoms. This is particularly true in case of severe or chronic calorie restriction. So, if you want to lose weight sustainably, ensure that you eat at least 1, 200 calories every day. Apart from this, make sure that you pay attention to the above signs so that you could know when to start eating more and keep away from any problem that might occur due to undereating.

We would also like to mention that if you are experiencing any of these important signs your body says you are not eating enough, talk to your doctor or a dietitian and take professional advice and take help in formulating a healthy diet plan for you.


Team PainAssist
Team PainAssist
Written, Edited or Reviewed By: Team PainAssist, Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:October 20, 2021

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