On Cooper's site 'My Food Religion', she does highlight how every body is different, so there's no 'one diet fits all' rule - you have have to find the right diet for your body. She explains, " The thing with food and nutrition is, everyone's body responds differently to different macro and micro-nutrients...
You can't "broad brush" nutrition which is why so many "diets" fail, they are not one size fits all. Our digestive and physiological make-up are a direct result of a life-time of conditioning: How many meals/day are you used to consuming, how large or small are your portions, have you consumed predominately carbs, proteins or fats throughout your 'eating life'?