Very true.Note that non vegetarian food is excluded.
Indian Philosophical treatises stress the fact that natural food is to be consumed.
Human Nature is broadly divided into three categories.
Contented,self reliant and calm
Highly energetic,active and passionate .
Inactive,dull and depressed.
These three characteristics are present in every human being and the combination of these factors vary depending on predisposition, and habit.Also these characteristics vary from one moment to another.
The first mentioned is ideal when you become healthy, strong both physically and mentally.You shall be in control of your mind and emotions and you shall be self reliant and self contented.
This can be achieved by diet;for your thinking is determined by what you eat and you become what you think.
For instance if you take pungent, spicy food you become hyperactive , easily swayed by emotions.On the other hand if you take mainly dairy food and vegetables you not only become healthy but you can manage your emotions.
Therefore Diet is given pride of place in Indian Philosophy.
There are foods to avoid.
-Spicy,pungent,stale,food that is too hot or that is too cold;
that is not cleaned,that is not over cooked;non vegetarian food including egg.
Suggested food.
Grains, Vegetables,roots,Milk products
Also it is necessary that the food be prepared by people who love you.In fact Sanskrit texts say 'That food is best that is prepared by self; next that is prepared by one's Mother,Sister,Daughter and Wife in that order.Any thing other than this is equivalent to poison'
mental vibrations do play an important part in preparing the food.