Blood Type DietGeno Type diet

Dr Peter D'Adamo, the designer of the Blood Type Diet, claims to have taken his original blood-type research a step further, and discovered that your genes can dictate which foods will make us more likely to gain or lose weight. He says: "We all fall into six basic gene types but you don't need a blood test to determine which one you are." According to Dr D'Adamo, each "genotype" has its own characteristics regarding weight and metabolism, which is why each needs its own diet.

Which celebs have been on it: Oprah Winfrey.

More celebrity & popular diets

Check out the latest, the greatest, the weirdest and the wackiest diets that are or have been popular: Atkins Diet : 5 Factor Diet : The Maple Syrup Diet : Dr Joshi's Holistic Detox Diet : The Hampton's Diet : The 3-Hour Diet : The Macrobiotic Diet : The Raw Food Diet : The Zone Diet : The Blood Type Diet : The Geno Type Diet : The Sugar Busters Diet