What is the Ketogenic Diet and What Foods are Acceptable?

The ketogenic diet is a low carbohydrate (carb) diet designed to change the energy source of the brain from sugar to fats (ketones) and to increase the use of fats as an energy source in the body as a whole by severely restricting the intake of dietary carbohydrates. It overlaps a lot with the Paleo diet in that the ketogenic diet consists largely of meats and fats.

For the ketogenic diet, fish are good choices. Full-fat dairy is allowed, but fermented and unsweetened ones are preferred. Fruits are quite limited though, to small amounts of berries, plus lemons and limes in moderation, and olives and avocado (these two are fatty fruits, rather than sugary). Vegetables consist mostly of non-root ones because those have more carbs. Legumes are largely avoided, except small amounts of green beans and peas.  Nuts and seeds are used in moderation as they have some carbs; but avoid peanuts, which are legumes, not nuts. 

Fats represent most calories in the ketogenic diet: avocado oil, coconut oil, olive oil, butter, cocoa butter, MCT oil, and nut oils in moderation (i.e. walnut, sesame). Eggs and unsweetened gelatin are fine. Processed foods and condiments that have added sugars or carbohydrates should be avoided. Sugar alcohols are also avoided; stevia is acceptable, but watch for added carbohydrates in some stevia products.

Unsweetened whey protein isolate (not concentrate) has the least amount of lactose of the milk proteins; unsweetened egg white protein is also fine. Though legumes are avoided if they have carbs, unsweetened pea protein or soy protein isolates are acceptable options in the ketogenic diet.  

Facts About Xylitol

Because of recent confusion and mis-statements by some bloggers, I'd like to report some facts about the sugar alcohol, Xylitol:

Like all sugar alcohols, unabsorbed (versus undigested) material is hygroscopic (attracts water) as it passes through the GI tract. This makes them potentially laxative at various doses; as always, moderation is the key.
o For xylitol, the common threshold is at 30-50 grams a day (1-2 ounces).
o For erythritol, an alternative sugar alcohol, there is practically no laxative effect since it is predominantly absorbed.

Xylitol is naturally found in plums, raspberries, and cauliflower; it is a naturally occurring sweetener that the body can handle.

Xylitol can be made from xylan; a fiber found in many plants including:
o corn husks, cobs, and stalks (corn bobs are the leading commercial source)
o certain hardwoods like birch and beech (relatively small commercial production is done in Europe for Scandinavian trees)
o rice, oat, wheat and cotton seed hulls (possible, but not a typical commercial source)
o various nut shells (possible, but not a typical commercial source)
o straw (possible, but not a typical commercial source)
o sugar cane (possible, but not a typical commercial source)

Xylitol does not require insulin.

Xylitol improves bone and tooth density, protects tooth enamel.

Xylitol has fewer calories than sugar; only about 2.4 calories per gram versus 4 for sugar.

Most xylitol is produced in China.
o However, GMO corn is not allowed for food production in China.
o There are some IP (documented as from non-GMO corn) supplies and others tested as non-GMO (the corn sources are tested before production, though IP is not in place yet).
o GMOs have not been found in xylitol from corn, despite unsubstantiated speculation from bloggers.
o China’s food safety laws have been expanded dramatically in recent years, and in some cases now exceed US standards.

Xylitol can be toxic to dogs, but so is chocolate. Pets can’t always eat our foods, but that doesn’t imply that these foods are somehow harmful to humans. This is a “straw man” argument that fades upon examination.