Are faddy diets harmful?

Fat-free diet

Why do it?

Fat has nine calories per gram, which is more than in protein, carbs or alcohol. So reducing your fat intake is the most efficient way to lose weight.

What can go wrong?

Really low-fat diets are linked to depression. Your skin will suffer too, becoming dry. Fat is needed for sex hormone production, too; if you cut your intake too low, your fertility and even libido could suffer.

Do it safely

Just cut down on fat rather than attempting to cut it out altogether, and shift the balance of fats you do have so you're having more unsaturated fats in olive oil dressings, nuts, seeds, avocados and oily fish. The absolute minimum amount of fat you should have every day is around 25g.