Good

“Good” is relative.  Most important is avoiding food and drink that are actually bad for you; avoiding pathology.  There are an array of diets that can accomplish that as long as you avoid sugars and easily digested carbohydrates that become sugar.  You can consume a diet where most of your calories come from not-so-easily-digested carbohydrates (vegetables, fruits, whole grains) and your organ systems use glucose.  You’ll get some benefits from that.  However, there’s another level to this, one I prefer.  If you drop carbs to under 100 grams/day such that you’re getting 60% or more of your calories from healthy fats, your metabolism will change.  After 14 days, you’ll adapt to using ketone molecules, which come from fats, in place of glucose.  That results in dramatically improved energy, endurance, and recovery.