Most diets fail. I’m not sure if this “fact” is actually true, but it’s repeated often enough to make me think there’s something to it. It also just seems likely to be true. During my second year of university, I gained about 20 - 30 lbs and tried to shed it quickly by adopting a Very Low Calorie Diet, something recommended for morbidly obese people. I wasn’t morbidly obese, I was just on the cusp of being overweight - my BMI was probably around 24 or 24.5 (overweight is 25).