The first statement is totally wrong. It is good to be in touch with your body's intelligence. It is designed to keep you healthy. It is what animals use even though they have not been taught what to eat. They way to turn this on is by fasting. Moses and Jesus fasted but so do many animals.
The way you know what foods are good for health, just eat what tastes good and that is best for health. Read this article,
Using Your Animal Instincts to Lose Weight. Rats know what to eat by instinct but man has made rat poison which fools them. Scientifically speaking, the sugar in fruit enters your blood very slowly. The home page of above site explains that fruit is the healthiest food. What do you call people who only eat meat? They do not have a name since there are not any except Dr Salisbury (RIP). There are thousands of fruitarians (only eat fruit) in America.
That site above has a link to a picture of one who is a bodybuilder. I am not saying that you should be one. The healthiset foods for you to eat are those created by nature or God. The worst ones are the ones made by man. The latter are designed to make you fat and addicted to eating a lot of their foods so you will buy lots of them. This is good business. Now in America you have a big group of people (that is growing) that only eat raw food. All the animals eat raw food except for monkeys, apes, racoons, beavers and people. Just kidding. Man is the only animal that cooks food.
Also man uses chemical pesticides when growing food which is against the law in Russia. Doing it there makes you a criminal. Also man genetically modifies food including fruits. But our capitalistic society is based on one thing and that is profit or money. It is not based on health. No animals smoke cigarettes either. Although since fruit passes through your stomach quickly, it should be eaten alone not with some meat, potaoes and ice cream.
In school, kids learn how to count money at an early age but are not taught anything about eating healthy. Most Americans do not know that all plant foods have plenty of fiber, unless man has taken it out. Animal foods have no fiber. Fruit can have different types of fiber like gums and pectins but candy has no fiber. Also it is healthier to eat water than to drink water. The above mentioned fruitarian bodybuilder has not drank any liquids for over a year.
Also man puts salt in food. A quarter pounder is 4 ounces. You can eat 10 of them together and not die. Put 4 ounces of salt in some water and drink it and you will die. That is about 120,000 milligrams of salt. There is a technique to never overeat any food. Eat the raw food alone and not combined with any other foods. Your body's intelligence will keep you from overeating. There are people who eat only this way. They are called instinctos. Science is constantly discovering that they are wrong. Also many studies are paid for by food companies.