The Side Effects of Under Eating

1) Concentration and thinking (learning impact)

The PDF explains that concentration is often impaired, even if a pupil seems driven or unusually focused for short bursts. It also highlights that constant thinking about food and weight can interfere with attention and learning.

2) Mood and emotions (wellbeing impact)

The resource outlines that under-eating can affect mood, including low mood, irritability, and feeling “spaced out.” It explains that nutrients influence emotional centres in the brain, so under-fuelling can make emotional regulation harder.

3) Obsession about food and weight (behaviour changes)

A common side effect of under-eating is increased preoccupation with food and weight. The PDF notes that some pupils become suddenly interested in cooking, recipes, and nutrition content, and may drop other hobbies.

4) Digestion, bloating, and appetite changes

The PDF explains that under-eating can slow digestion and cause discomfort, fullness sensitivity, constipation, and bloating. It also clarifies that bloating can be caused by under-eating, and can occur when intake increases, often settling over time.

5) Energy, sleep, and low blood sugar

The resource links low blood sugar and low fuel to fatigue and reduced ability to cope with school demands. It also notes sleep disruption, early waking, and restlessness.

6) Hormones, periods, and bone health

The PDF explains that the body can reduce sex hormone production, which may affect libido and lead to delayed or absent menstruation. It also notes that nutritional imbalances can increase osteoporosis risk later in life.

7) The 12 symptoms of under eating (visual checklist)

A visual summary lists signs teachers may notice, including: low energy, frequent illness, increased injuries, constipation, no appetite, caffeine dependency, counting macros and calories, frequent waking, irritability, low mood, bloating, and lack of menstruation.