Why you should avoid yo-yo diets

How does Britney drop 5 kilos in a few days - then seems to be back where she started a few weeks later? And how does Jessica Simpson morph from buxom blonde to a denim shorts-clad leggy lass, only to go back to being curvy again? Yo-yo dieting is rampant in celeb-town, but it's one trend that you shouldn't follow. The combination of near starvation and vigorous workouts is bad for your figure and worse for your health. The "starving" phase can't be maintained long and will almost always be followed by "stuffing", when your body compensates for everything you have denied yourself. Severely restricting calories also puts the body into starvation mode where it becomes efficient at protecting fat stores and uses muscle to provide calories - so we lose muscle mass. When you start eating normally, the body can't burn calories like before and you pile on fat. Slashing food means losing fibre and nutrients, so hair, skin and nails start to look dull and flaky and you could suffer headaches, dizziness, irritability and fatigue. Long-term fluctuating body weight has been associated with coronary heart disease, high blood pressure, high cholesterol and gallstones. Then there's the psychological impact. Research reveals that constantly losing and gaining weight can increase stress and make you feel depressed. Of course, obesity comes with health problems like heart disease, Type 2 diabetes, certain cancers and joint and back problems - so it makes real sense to get yourself in shape. But if you want to stay healthy and look fantastic, then lose those extra pounds gradually and don't go to extremes. Then keep them off for good with a balanced diet and regular exercise. What's your perfect weight? - Calculate your Body Mass Index (BMI). Use an on-line calculator for a BMI of 21. - Get a tape measure and measure your waist. For women, it should be below 32 inches. - Measure your percentage body fat. Many weighing scales now also measure body fat and some gyms have facilities to do this. A healthy range of body fat for women aged 20 to 39 years is 21 to 33 per cent.