The principle of ketogenic diet is fairly simple - you eat very little or none carbohydrates at all . This makes your body enter ketosis and release ketones into your body, which starts using fat (instead of carbohydrates) as a fuel.
Ketogenic diet is believed to shred your body fat while preserving muscles.
It is supposed to look like this: 5 or 6 days of low carbs (I suggest no more than 30 grams), and 1 or 2 days of high carbs.
Since you can't eat any full-carb foods, you will need a lot of fat for energy, and a lot of protein to preserve your muscles.
Examples of food you can safey eat and remain in ketosis: Beef, Steak, Hamburger, Prime Rib, Filet Mignon, Roast Beef, Chicken,
Duck, Any Fish, Tuna, Salmon, Trout, Halibut, Lamb, Pork, Bacon,
Ham, Eggs, Shrimp, Crab, Lobster, Butter, Oils (Olive Oil, Flaxseed
oil, etc.), Mustard, Salt, Pepper, Soy Sauce, Tea, Coffee
Now these food contain some carbs, so eat only in limited quantities: Broccoli, Spinach, Lettuce, Cabbage, Bok Choy, Kale, Asparagus,
Mustard Greens, Mushrooms, Cucumbers, Pickles, Celery, Green
Beans, Brussel Sprouts, Cauliflower, Artichokes, Peppers (Red,
Green, Jalapeno, Habanero), Onions, Sprouts (bean, alfalfa, etc.),
Radicchio and endive, Herbs - parsley, cilantro, basil, rosemary, thyme etc, Radishes, Sea Vegetables (Nori, etc), Jicama, Avocado, Asparagus, Green Beans and Wax Beans, Broccoli, Summer Squash, Zuchinni, Scallions or green onions, Bamboo Shoots, Leeks, Brussels Sprouts, Snow Peas (pods), Tomatoes, Eggplant, Tomatillos, Artichokes, Fennel, Okra, Spaghetti Squash, Celery Root (Celeriac), Turnip, Water Chestnuts, Pumpkin, Nuts, Flaxseeds, Cheeses, Salami, Pastrami, Hot Dogs, Sausages, Ribs, Buffalo Wings, Liverwurst, Oysters, Abalone, Protein Powders
And finally a list of stuff you can't eat at all: Beer, Mixed drinks, Bread, Milk, Pasta, Grains, Cereal, Rice, Potatoes,
Corn, Carrots, Peas, Candy, Cake, Cheesecake, biscuits, Donuts, Fruit
Juices, High Carb Fruits (Apricots, grapes, Bananas, Peaches,
Nectarines, cherries, Pomegranates, Mangos, Figs, Dried Fruit, such as dates, raisins, dried apricots, and prunes etc.),
Pastries, Non-Diet Soft Drinks, Rolls, Bagels, Popcorn, Battered Foods
(Fried Chicken, etc.), Gravy, Honey, Sugar, chocolate and Corn Syrup.