Fats turn into lipids? All fats ARE lipids. DUH. From dictionary.com:
lip·id /ˈlɪpɪd, ˈlaɪpɪd/ Pronunciation Key - Show Spelled Pronunciation[lip-id, lahy-pid] Pronunciation Key - Show IPA Pronunciation
any of a group of organic compounds that are greasy to the touch, insoluble in water, and soluble in alcohol and ether: lipids comprise the fats and other esters with analogous properties and constitute, with proteins and carbohydrates, the chief structural components of living cells.
There are times when sugars are good, times when fats are good, and times when both are bad.
E.g. Post workout, while you're in the "golden hour" sugar is ideal for pushing glycogen into your muscles.
Polyunsaturated and mono-unsaturated fats are good for you. Read this article from the renowned Mayo Clinic:http://www.mayoclinic.com/health/fat/NU00262
You have to eat for your goals and performance. It's science.
With regard to fiber, the best way to get it is to take it directly. Citrucel, Metamucil, etc.
Protein = 4 kcal
Carbs = 4 kcal
Alcohol = 7 kcal
Fats = 9 kcal to 11 kcal.
Before you guys start talking out your ass, do some research first.
The answer to your question is contingent to time of day, your activity, your goal, and body type. There's not one size fits all answer.