Doing this sounds easy enough, but in practice it is much harder to achieve. For example, in the animal kingdom instinct is what drives animals to eat. Lions are meat eaters. Conversely, other animals are vegetarian, and by instinct, will not eat meat. This is no accident.
Instinct is a protective mechanism for all animals, including humans.
The problem is humans are so domesticated, instinct no longer drives their eating habits. What we can learn from animals is they eat only what is instinctively good for them, and as a result heart disease is virtually non-existent. While animals occasionally do develop cancer, statistically it occurs dramatically less often than in humans. Well, this is because of their uniform diets, driven by instinct, that allow them to have life spans to the potential of their species. Another point to remember is most animals that are not killed by predators die of old age, or what we call natural causes.