Part one of two. Documentary examining the often dangerous and misguided methods adopted to lose weight, as scientists, industry experts and exponents explain the pros and cons of fad diets, so-called healthy foods and extreme exercise regimens. Side-effects revealed include incontinence, infertility, infected genitalia, the need for hip replacements and in some cases death, as well as instances of botched surgeries, risky diets that are detrimental to health and bizarre fitness programmes.