When someone is undereating, they are consuming fewer calories than their body needs to function correctly. This can have a severe impact on energy levels, causing feelings of physical tiredness and mental fatigue, which may impair a person's daily functioning.

Is Undereating as bad as overeating?

You'll be hungrier on the days that you undereat, which will make you more likely to overeat again. Suddenly, one day of overeating becomes a rollercoaster week of overeating, undereating and overeating again. You'll have a better chance of getting back on track by eating your regularly prescribed macros the next day.

What happens when you eat too little?

In addition to sabotaging your weight-loss efforts, eating too few calories can also harm your health. When your body goes into starvation mode, you are at increased risk for the following: Abnormally low blood pressure and slow heart rate. Heart rhythm abnormalities.