Intentional or otherwise, under-eating is incredibly common. Under-eating – or under-fuelling – essentially creates an energy deficit. This is where energy intake (via food) is less than the energy we expend. It can occur for a variety of reasons including:
- Caloric restriction for weight loss
- Disordered eating
- High levels of stress
- Poor appetite
- Gut symptoms such as diarrhoea, constipation, bloating, and nausea
- High exercise load
- Increase energy demands (e.g. during breastfeeding, injury and illness)
Even if weight loss is your goal, it’s especially important that your nutritional requirements continue to be met. Maintaining an adequate intake of all nutrients is necessary to prevent deficiencies and maintain normal body systems (such as the digestive, reproductive and immune systems).
“How will I know?”
The body is intelligent and will tell you what it needs. To gauge whether you’re meeting your energy requirements, we invite you to tune in and listen to its signals. Tracking calories is not necessary for the average person. It certainly isn’t appropriate for those with a history of (or susceptibility to) disordered eating. Food is so much more than fuel (or calories) alone.
Indicators of under-eating
Experiencing any of the following may indicate under-eating, signalling a need to increase food intake overall:
- Hunger. Although seemingly self-explanatory, feeling quite hungry in between (or even soon after) meals may be a sign that you’re needing more food. Waking up hungry during the night is also an indicator that you’re under-fuelling,
- Low energy and/or fatigue. Given that we derive our energy from the foods we eat, it’s unsurprising that under-eating leads to lethargy and sluggishness. If you’re getting enough quality sleep but still feeling fatigued during the day, try having something to eat instead of reaching for that extra coffee, and see how you feel.
- Light-headedness, dizziness and/or poor concentration. Feeling light-headed, dizzy or faint are among the early, physical signs of hunger, and can occur in response to low blood sugar levels.
- Gastrointestinal symptoms including reflux, nausea, bloating, abdominal pain and constipation. Like all organs in the body, the gut needs enough energy to function at its best. Where energy intake is insufficient for the body’s requirements, the body will deliver energy to other, more critical organs such as the brain, heart and lungs. Digestive enzyme production also declines, further exacerbating gastrointestinal symptoms and compromising nutrient absorption.
- Absent periods. Being underweight, a low body fat percentage, or simply under-fuelling the body can affect hormone production and stop ovulation, leading to an absent or irregular cycle. A loss of menstrual function is a clear signal from the body, and should be addressed swiftly to prevent further negative health consequences. It indicates a decline in oestrogen levels, which can adversely affect fertility and bone health.
- Low libido. Hormonal changes associated with under-eating can also affect libido. When under-fuelling, libidio will drop in our body’s attempt to avoid creating pregnancy as it feels there isn’t enough energy available to safely do so.
- Hair loss and/or breakage, brittle nails. The redirection of nutrients to more critical, life-supporting processes in the body means fewer are available to support hair and nail health.
- Changes in mood. ‘Hanger’, irritability, or low mood can result from under-eating, further indicating that simply eating enough supports us to be our best, healthiest selves.
- Poor performance in sport, training or the gym. Active individuals require more fuel than less active individuals, to meet the associated physical demands on the body. When the body isn’t appropriately fuelled, poor performance, impaired recovery and injury can result.
- Frequent illness. Under-eating can also compromise immune function. An ongoing, insufficient intake of nutrients that support the growth and function of immune cells, leaves the body ill-equipped to defend against infection. Vitamin C, zinc, iron, selenium and protein are all critically important, immune-supporting nutrients.
For expert dietary advice to meet your unique requirements and support you on your way to optimal health, book your first appointment with one of our wonderful Accredited Practising Dietitians today.
Written by Caitlin Branch, Student Nutritionist, and Amanda Smith, Accredited Practising Dietitian.