Without going into it. Fats can be used as your primary source of energy (Keto diet). I'm too lazy to post an in depth response at the moment but I will later tonight.
NATURAL peanut butter is great while following a keto diet.
The keto diet is a high fat, moderate protein and extremely low carbohydrate diet, where the brain uses ketone bodies (fats) instead of carbs to fuel the body. When in ketosis the brain uses the fats ingested as its primary energy source sparing the protein ingested allowing this to go towards muscle growth/repair. Remember it takes 3-4 days to get into a strong ketosis so patience is needed.
To enter into ketosis the macronutrients levels that should be ingested are as follows 1.5g of protein per lb of bodyweight, 0.5g of fat per lb, and whatever residual trace carbohydrates are eaten.
Food sources:
Protein Sources
§ Chicken
§ Beef
§ Fish
§ Eggs
§ Bacon
§ Pork
§ Lamb
§ Mince
§ Hamburger Patties
Fats
§ Butter
§ Cheese
§ Extra Virgin Olive Oil
§ Macadamia Oil
§ Coconut
§ Brazil Nuts
§ Almonds
§ Walnuts
§ Macadamias
§ Natural Peanut Butter
Vegetables
§ Green Beans
§ Broccoli
§ Baby Spinach
§ Lettuce
§ Celery
§ Avocado
§ Asparagus
§ Watercress
§ Spring Onions
§ Mushrooms