The problem with the high-protein, low-carbohydrate diets popular at the moment is interpretation. It's when people look for a quick fix that the problems start. They cut out all carbohydrates for a week or so, then go back to their usual bad eating habits.

There are some serious health risks around high-protein diets. Protein causes acidity in the body; excessive acidity can cause the body to release the alkali found in your bones, and may even increase the risk of some cancers. Eating a lot of meat has also been linked to cancer of the colon.

Complex carbs, found in foods such as rice and potatoes, are needed for fibre, vitamins, minerals and essential fats. We do need to watch our intake: most of us lead sedentary lives and need nowhere near the amount of carbs we consume. I advise clients to follow a "glycaemic loading diet", which is about combining the right proteins with the right starchy carbohydrates to give steady, slow-release energy.

To work out how much of each food group you should be eating, lay your hands out flat and draw round them: this will show you how big your plate should be. At lunchtime, fill your plate with vegetables to about the size of your left hand; about half the other hand should be lean protein, and half starchy, wholegrain carbs such as rice, pasta or quinoa.

At dinnertime, unless you're going to be exercising, make it half a hand of lean protein and the rest vegetables. Leave out the carbs. Eat like this, and you are likely to lose excess fat and reach your body's natural weight – and most importantly, you won't be yo-yoing from one faddy diet to another.

Yvonne Bishop-Weston is a London-based nutritionist; optimumnutritionists.com