I don’t understand," I heard a woman telling her friend in the gym changing rooms. "I’m not eating any sugar and I’m exercising six days a week but I just can’t lose this layer of fat." She pulled at her stomach and her upper arms. Her friend nodded empathetically and pulled at her own wobbly bits.

As they related details of their healthy, disciplined lifestyles to each other, I had to agree that they were doing everything right. So why were they both struggling?

Going to the gym or eating less might not be the best approach. Your efforts might be making the situation worse

It may be unfair, but this mismatch between lifestyle and appearance is not uncommon. The truth is that, male or female, tall or short, young or old, it's not always just nutrition and movement that causes us to look the way we do; getting in shape is more complicated than doing more and eating less.

First, as most of us accept, there can be a genetic element to where we store fat. If your mother complained of bingo wings, then regardless of how many tricep dips you do, you might still have a wobble there.

Even if you exercise well, you might not see results Credit: Johner Images / Alamy

Second, and less commonly understood, there's your endocrine system or your hormones, which can greatly affect how you look and feel, even if you have a good diet and training regime.

Sally Norton, a surgeon, agrees. "Medical conditions that cause a low thyroid hormone level or a very high cortisol level can lead to significant weight gain," she says. "It appears that elevated cortisol hormones as a result of stress may increase fat deposition around the waist (belly fat), a pattern which is associated with diabetes and heart disease."

People who are exercising a lot and eating well but still struggling to lose fat, should consider swapping high-intensity or endurance exercises for low-intensity yoga and long, gentle walks

This link is backed up by a Yale University study published in 2000 in the Journal of Psychosomatic Medicine. However, adds Norton: "Eating too many doughnuts or sitting around all day is [still a] much more common as a cause of weight problems."

If you are eating a balanced diet with sensible portion sizes and doing regular exercise, it may be time to turn down the volume on your stress hormones.

Try low-intensity yoga if you're struggling Credit: © Anna Omelchenko / Alamy/Anna Omelchenko / Alamy

Keris Marsden, a health expert and co-founder of Fitter Food, suggests that people who are exercising a lot and eating well but still struggling to lose fat, should consider swapping high-intensity or endurance exercises for low-intensity yoga and long, gentle walks. During this time, they should avoid processed food as this places extra stress on the body. Marsden also recommends that people eat four or five smaller meals to keep their blood sugar levels balanced. Eating healthy fats such as coconut oil, extra virgin olive oil and organic butter can help, too.

She also advises people to eat more protein. "This helps to rebalance oestrogen and progesterone levels, reduce cortisol, and stabilise mood and energy, so you no longer need to rely on health hijackers like caffeine and sugar," says Marsden.

Finally, people should consider taking supplements. "Magnesium, zinc, B vitamins and omega 3 supplements also rebalance progesterone and oestrogen," she says.

Make sure you're getting a good nights sleep Credit: Alamy

It might seem counterintuitive when you are finding it hard to build muscle or lose fat, but if you’ve been pounding the treadmill for years to no avail, then going to the gym or eating less might not be the best approach. Your efforts might be making the situation worse: overtraining and anxiety increase cortisol and deplete the hormone progesterone, which stops fat being deposited around the middle.

Instead, sleep as much as you can and include at least 15 minutes of daily meditation in your routine. After a month, you can reintroduce a more intense type of yoga, such as vinyasa flow or ashtanga, and perhaps increase the pace of your walking. Eight to nine hours sleep a night should still be a priority.