TABLE 1.

Simplified Copy of Dietary Instruction Given for Each Patient in a Specific Diet Group

Diet	Description	Allowed foods	Forbidden foods
A	High-fat, low-carbohydrate diet beginning 24 h before the study. Nothing by mouth, except water and oral pills, 6 h before the examination.	Beverages: club soda, black coffee, tea (without sugar), or water. Seasonings: anything that does not contain sugar. Fats/oils: butter, margarine, or vegetable oils. Eggs. Meat: chicken, turkey, fish, beef, or pork (watch closely for sugars in processed meats), meat-only sausages, and nonsweetened bacon. Shellfish: any nonprocessed shellfish. Vegetables: alfalfa sprouts, artichokes, asparagus, bean sprouts, broccoli, Brussels sprouts, cabbage, celery, cucumber, eggplant, any lettuce	No carbohydrate or sugars. Anything with glucose, fructose, sucrose, or lactose. No artificial sweeteners. No fruit or fruit juices. No diet or regular sodas or sports drinks. No alcohol. No dairy products such as milk, cheese, cream, or yogurt. No pastas, breads, cereals, rice, bagels, crackers, or muffins. No breading on any food. No candy, cookies, or cake. No gum, mints, or cough drops. No condiments such as ketchup and mustard with sugar in it. No starchy vegetables such as corn, peas, carrots, most legumes, grains, and potatoes.
B	18 h of fasting before the study. Nothing by mouth, except water and oral pills, for 18 h before the study.
C	High-fat, low-carbohydrate ketogenic diet beginning 72 h before the study. Nothing by mouth, except water and oral pills, for 3 overnight fasts before the exam. First 2 nights from 08:00 pm until at least 08:00 am the next morning. The night before the test from 08:00 pm until the time of the test. For diabetics, consider avoiding prolonged fasting, preferably obtain the examination at noon hours after ketogenic breakfast + morning insulin, followed by 6-h fasting.	Beverages: club soda, black coffee, tea (without sugar), or water, Seasonings: anything that does not contain sugar. Fats/oils: butter, margarine, or vegetable oils. Eggs. Meat: chicken, turkey, fish, beef, or pork (watch closely for sugars in processed meats), meat-only sausages, and nonsweetened bacon. Shellfish: any nonprocessed shellfish	No carbohydrate or sugars. Anything with glucose, fructose, sucrose, or lactose. No artificial sweeteners. No fruit or fruit juices. No diet or regular sodas or sports drinks. No alcohol. No dairy products such as milk, cheese, cream, or yogurt. No pastas, breads, cereals, rice, bagels, crackers, or muffins. No breading on any food. No candy, cookies, or cake. No gum, mints, or cough drops. No condiments such as ketchup and mustard with sugar in it. Vegetables are not permitted. No beans or nuts.