As Michael Dansingel, MD from the Academy of Nutrition and Dietetics said: "First, if a diet sounds too good to be true, it probably is. Second, if you can’t see yourself following the diet for the rest of your life, it’s not for you." This basically holds true to the 3 day Military Diet: it sounds magical, yet when you take a closer look, you realize its pitfalls.
But you’ll likely experience some benefit before then. Fiber helps slow down your digestion and requires more chewing, which helps signal to your body that it’s full, keeping your hunger in check throughout the day. One small study published in Food & Nutrition Research actually found that men who ate meals rich in high-fiber foods, like beans and peas, felt more satisfied than those who focused only on protein-rich foods, like pork and veal. Adult women should aim to eat 25 to 28 grams of fiber per day.
According to Mike Russell, MD: "If you weigh 180 pounds and your goal weight is 130 pounds, losing 20 pounds in one week—the right way—teeters on the brink of impossible. If you’re more like a Biggest Loser contestant, weighing 380 pounds, then losing 20 pounds in one week is plausible (especially considering a large amount of water weight you would lose during the first week)."
Low-calorie diets: It is harmful to reduce your daily calorie intake lower than 1400 calories per day, because your body adjusts to a semi-starvation state and looks for alternative sources of energy. In addition to burning fat, your body will eventually burn muscle tissue. Because your heart is a muscle, prolonged starvation will weaken it and interfere with its normal rhythms. Low-calorie diets don't meet the body's nutrition needs, and without nutrients your body cannot function normally.
For long-term success, it is recommended to avoid short fad diets and focus on a gradual lifestyle change. Start eliminating processed foods, and begin eating a mostly organic, plant-based whole food diet with plenty of vegetables, fruits, whole grains, seeds, nuts, beans, and legumes. Exercise at least 20 – 30 minutes a day. Get enough sleep, reduce stress, and practice a positive mindset.
Yancy WS Jr, Westman EC, McDuffie JR, Grambow SC, Jeffreys AS, Bolton J, Chalecki A, Oddone EZ, “A randomized trial of a low-carbohydrate diet vs orlistat plus a lowfat diet for weight loss,” Arch Intern Med. 2010 Jan 25;170(2):136-45. http://www.ncbi.nlm.nih.gov/pubmed/20101008?itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum&ordinalpos=2.