Prior to the advent of exogenous insulin for the treatment of diabetes mellitus in the 1920's, the mainstay of therapy was dietary modification. Diet recommendations in that era were aimed at controlling glycemia (actually, glycosuria) and were dramatically different from current low-fat, high-carbohydrate dietary recommendations for patients with diabetes [1,2]. For example, the Dr. Elliot Joslin Diabetic Diet in 1923 consisted of "meats, poultry, game, fish, clear soups, gelatin, eggs, butter, olive oil, coffee, tea" and contained approximately 5% of energy from carbohydrates, 20% from protein, and 75% from fat . A similar diet was advocated by Dr. Frederick Allen of the same era .
Reduced hunger. Many people experience a marked reduction in hunger on a keto diet. This may be caused by an increased ability of the body to be fueled by its fat stores. Many people feel great when they eat just once or twice a day, and may automatically end up doing a form of intermittent fasting. This saves time and money, while also speeding up weight loss.
The ketogenic diet seems straightforward. Unlike a typical low-calorie diet, however, a high-fat diet requires careful monitoring. In fact, you may start the diet in a hospital. Your doctor needs to monitor both blood glucose and ketone levels to make sure that the diet isn’t causing any adverse effects. Once your body adjusts to the diet, you may still need to see your doctor once or twice a month for testing and medication adjustments.
DASH is based on the following foods: fruits, vegetables, low fat milk, whole grains, fish, poultry, beans, and nuts. It recommends reducing sodium, foods and beverages with added sugars, and red meat. The diet is heart-friendly as it limits saturated and trans fat, while increasing the intake of potassium, magnesium, calcium, protein, and fiber, nutrients believed to help control blood pressure. 
^ Freeman JM, Vining EP, Pillas DJ, Pyzik PL, Casey JC, Kelly LM. The efficacy of the ketogenic diet—1998: a prospective evaluation of intervention in 150 children. Pediatrics. 1998 Dec;102(6):1358–63. doi:10.1542/peds.102.6.1358. PMID 9832569. https://web.archive.org/web/20040629224858/http://www.hopkinsmedicine.org/press/1998/DECEMBER/981207.HTM Lay summary]—JHMI Office of Communications and Public Affairs. Updated 7 December 1998. Cited 6 March 2008.