In their book „Mastering Leptin“ (2001), the authors Byron J. Richards and Mary Guignon Richards explain how obesity can be conquered, why diets do not work and how weight loss can be easy and long-lasting. Leptin is a hormone that assists in regulating appetite and the body’s metabolism. Leptin levels are generally proportional to body fat because leptin is released by fat cells. When leptin levels are high, our appetite is reduced and our metabolic rate increases. When leptin levels are low, our metabolic rate slows down and we feel hungry. It is believed that obese people may have developed leptin resistance and that their bodies fails to respond to leptin signals. In order to get our leptin hormone into balance, the authors suggest five basic rules.

The Warrior Diet was created by Ori Hofmekler, a former Penthouse magazine editor and former Israeli Special Forces Soldier, based on his own personal experiences. He argues that in order to succeed in the environment of the time, the historic „warrior“ had a primal need to cycle between undereating during the day, when physical danger was always present and he had to stay alert, and overeating at night, when he could afford to relax. According to Hofmekler, the undereating phase maximizes the sympathetic nervous system’s fight or flight reaction to stress, with the result of energy generation and ultimately fat burning.

The Scarsdale Medical Diet is a closely monitored regime over a two-week period under medical supervision. Weight loss is achieved by limiting consumption to about 1,000 calories a day, composed of 43% protein, 34,5% carbohydrates, and 22,5% fats. Oils, butters, and other fats are eliminated which encourages the body to metabolize existing stores of fat. It does not allow sugar or alcohol. The Scarsdale Medical Diet was developed by cardiologist Dr. Herman Tarnower who had been prescribing a two-week crash diet for his patients for many years before he published the book „The Complete Scarsdale Medical Diet“ in 1978. Many believe that it was Dr. Tarnower’s murder in 1980 that made the book a bestseller and keeps it popular today.

Developed by Ron Rosedale and Carol Colman, the Rosedale Diet is a diet plan designed to help control leptin, the key hormone that regulates appetite. It is a high fat, very low carbohydrate, and low protein diet and in that similar to the South Beach Diet, the Hampton’s Diet, and also the Atkins Diet. However, it places emphasis on eating good, unsaturated fats and avoiding saturated or trans-fats. The diet begins with a 3-week phase where all starchy carbohydrates are to be avoided. After that, some starchy carbohydrates are allowed, but only in restricted amounts.

The Pritikin Eating Plan in based on the assumption that people crave fatty foods by nature and that hunger triggers the „fat instinct“ and awakens these cravings. Sugar or sugary foods can also make us want to overeat. With five simple steps we can outsmart the instinct: exercise, eat the right carbohydrates, eat less fat, eat frequently, and maintain a consistent style of eating. In order to make the program work, it is necessary to follow every single step.

The Hamptons Diet, developed by Fred Pescatore, a former medical director of the Atkins Diet Center, seems to be a mixture of the Atkins Diet, the South Beach Diet, and The Mediterranean Diet. It is a low-carbohydrate diet with – and this is new - special emphasis on the right kind of fats, especially monounsaturated fats, and among these, Macadamia nut oil is praised as a „secret ingredient“ for weight loss. Apparently Macadamia nut oil is richer in monounsaturated fats than other nut oils and olive oils. Further, the consumption of fish is recommended, particularly salmon and other fish rich in omega-3 fatty acids.

The Shangri-La diet is the result of fifteen years of self-experimentation by professor Seth Roberts. He found a direct correlation between the abundance of flavors in our modern food and fat storage. He therefore concluded that eating tasteless food will send signals to the body to reduce calorie intake.

Pine nuts, which are actually seeds, not nuts, have been known since before ancient Greek and Roman times.

The body for life program is a 12 week exercise and diet program which was created by Bill Phillips, a former competitive body-builder. It consists of daily, brief, progressive workouts, and six meals a day, consisting of a portion of protein, carbohydrates, and vegetables. The size of each portion is reduced to the size of the dieter’s palm and the dieter is told to drink at least 10 cups of water a day.

The South Beach Diet was developed by cardiologist Dr. Arthur Agatston for his chronically overweight heart patients. He emphasizes the consumption of good carbohydrates and good fat as opposed to the bad carbohydrates found in foods with a high glycemic index, and bad fat such as saturated fat and trans fat. In April 2003 he published his diet program in the book called „The South Beach Diet: The Delicious, Doctor-Designed, Foolproof Plan for Fast and Healthy Weight Loss“.

The 90/10 Weight Loss Plan was developed by Joy Bauer, a leading nutrition authority, who is also author of the highly respected „The Complete Idiot’s Guide to Total Nutrition“. The 90/10 Weight Loss Plan is based on the premise that if we balance our food intake by eating 90 percent healthy, nutritious food, we can indulge in „fun food“ for the remaining 10 percent.

The New Beverly Hills Diet, developed by Judy Mazel, is based on the assumption that enzymes found in food „activate“ the human body and that each of the three food groups, carbohydrates, proteins, and fats, contain their own set of enzymes to break down food so that the body can properly digest it. It thus recommends „cautious combining“ which means, that it matters when we eat and what foods we eat together. In order for food to be properly digested and not stored as body fat, we should eat fruit by itself and never eat protein together with carbohydrates. Judy Mazel claims that with her diet one can lose 10 to 15 pounds in 35 days.

The Zone diet is based on the theory that excess insulin, the hormone that helps control our blood sugar levels, makes us fat and keeps us from losing weight. By regulating our blood sugar levels, the body burns fat more efficiently and we lose weight. To control our blood sugar and therefore insulin levels, we need to get the proper balance of carbohydrates, proteins, and fats in every meal. If we follow a low-carbohydrate, high-protein diet with moderate amounts of fat, the hormones can be balanced within the preferred „zone“.