Q: My 17-year-old son constantly complains of hunger, even after he has just had dinner an hour earlier.
He does not seem to gain weight, even though he eats a lot.
His friend recommended that he take weight-gain supplements.
Why is my son so easily hungry and should he take supplements to help him gain weight? Should he eat more protein? Also, does he need a medical check-up?
A: Like many teenagers, your son has a good appetite because he is undergoing puberty.
He may also have a higher metabolic rate, so he does not put on weight as easily as others.
I would not recommend supplements, as a natural, balanced diet is better.
If you are concerned, it is best to have him see a doctor for a check-up.
It is unlikely that he has a disease if he is feeling well and does not suffer from any symptoms.
You should be concerned, however, if he complains of significant health symptoms.
Hyperthyroidism, for instance, can cause weight loss even though the person has a voracious appetite. This is a condition where the thyroid is overactive and produces too much of the hormone, thyroxine.
Besides weight loss, there are usually other symptoms, such as excessive sweating, heart palpitations or finger tremors, which may suggest this diagnosis.
In general, supplements should never take the place of a healthy diet consisting of nutritious food, even though some supplements are beneficial for overall health.
Moreover, artificial supplements, which may be expensive, are synthetic. Some supplements have strong active ingredients which may cause side effects, including allergic reactions.
Conversely, a balanced diet ensures that the individual will take the appropriate amount of all the main classes of food to ensure optimal growth and development.
Protein shakes and protein powders made into a drink are popular as a nutritional supplement.
Protein powders come in various forms, such as whey, soya and casein protein.
While it is true that protein is required to build muscle mass, there is a limit to the extent of muscle growth, no matter how much protein is consumed.
Eating protein alone will not increase muscle mass. To build muscle, you would still have to use your muscles and exercise.
The slight muscle damage which occurs during weight lifting and when doing resistance exercises is associated with healing and the muscle grows larger as a result.
For most people, adequate supplies of protein required for muscle growth are easily obtained from food sources, without the need to consume supplements like expensive protein shakes and powders.
However, do note that consuming extra protein adds extra calories. Any excess protein cannot be stored in its original form in the body. So, if these calories are not expended through physical activity, or by doing resistance exercises to build more muscle, they are converted into fat.
This would explain why an increase in protein intake, without an increase in physical activity, is likely to result in both fat and muscle gain.
As a general principle, protein should not make up more than 30 per cent of our daily caloric intake. In fact, 15 per cent would provide most people with sufficient protein.
If in doubt, check with your doctor.
Associate Professor Loke Kah Yin
Head and senior consultant at National University Hospital's division of paediatric endocrinology
This article was first published on September 15, 2015.
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