I am a very thin female amateur athlete. I desperately want to put on weight but I never seem to gain more than a couple of pounds. Please can you offer some advice?

Some people are "hard gainers" - that is, they require more effort than the average person to gain weight. Hard gainers have also been observed to burn more energy, as they tend to be more fidgety, finding it difficult to relax and sit quietly.

To optimise weight gain, you need to add muscle-building exercises three or four times a week, as well as eating more calories; this will stimulate muscular development and help convert the additional calories into muscle rather than flab. Regular strength workouts should increase muscle size through hypertrophy of the muscle fibres and localised additional blood flow.

Try to eat three meals a day, every day. Skipping meals or overeating one day and undereating the next will hinder weight gain. Eat larger portions at each meal: instead of one sandwich for lunch, eat two and drink a larger glass of milk. Eat extra snacks before bedtime - a hefty peanut butter sandwich and glass of juice, say. Mid-afternoon and mid-morning snacks are also beneficial, but check they do not curb your appetite for your lunch and dinner.

Boost calorie intake by drinking fruit juice and milk instead of water, and when training, quench thirst with calorie-containing fluids. Eat soups with a split pea or pulse base and choose calorie-dense fruit such as bananas. Putting this into practice may be hard but consistency will be key to your weight gain success.

Joanna Hall is a fitness expert (joannahall.com). Send your exercise questions to Weekend, 119 Farringdon Road, London EC1R 3ER. Email weekend@theguardian.com