Know your body
This may sound slightly raunchy and sexual, and it could be, but when it comes to diet, exercise and health, one of the first breakthroughs you can encounter is knowing your own body, well enough to know its limits, strengths, weaknesses and digestible capabilities.
Being able to know simply whether you are hungry is a skill that may take some time to master, and this is why raw food allows you to be more honest, because of the perpetual hunger experienced with cooked food, and always wanting to snack, even soon after meals. I find that when I mono eat bananas, I don't feel really hungry for sometimes seven hours after the meal, and only after I've exercised, so I'm making use of the carbohydrates and natural sugars to allow for better performance.
Then there will be times when I don't feel that hungry at a marked time during the day and so I will skip a meal, until I feel genuinely hungry again. There are no hard and fast rules for when you should eat and at what time of the day but the two main ideas are slow and fast metabolism. Sure eating fruit as opposed to cooked food/meat means metabolism will speed up anyway due to the instant assimilation of sugars the body and brain cry out for, but dependent on requirements, there are two basic principles.
For those wanting to lose weight small yet frequent meals should be eaten throughout the day, with a two-hour space minimum between meals. For those wanting to gain or maintain weight two or three main meals should be eaten consisting of a higher frequency of calories per meal, so the body's metabolism slows down and the food is better assimilated to increase mass i.e. muscle.
Knowing also what exercise you can do, half of which consists of training the mind and creating habits to exercise more, is key to establishing good health, because without exercise eating is meaningless because real hunger will rarely be experienced.
The one exercise that people will generally always have time for is also generally the most enjoyable, and that's when knowing your own body can really benefit!