For most people, a whole food, low carb high fat diet may be the most effective diet for losing weight or controlling blood sugar. These diets are often referred to nowadays as paleo diets, because they resemble the diet of prehistoric man in the Paleolithic Age. These diets restrict carbohydrates; restrict or prohibit grains; and emphasize protein and fat.
Current popular diets include the Primal Blueprint diet and the Paleo diet. Both are whole food diets that prohibit sugar and processed foods. Previous diets, successful for weight loss, but not necessarily entirely whole food diets, include the long-lost original Weight Watchers diet and the original Atkins diet.
For hundreds of thousands of years, people were hunter-gatherers who ate wild game, fruit, and vegetables. The human body evolved to eat this diet. Agriculture, to produce significant amounts of grains and beans, was developed only 10,000 years ago. We did not evolve to eat those kinds of carbohydrates.
The theory behind paleo diets: When we eat too much carbohydrate, we get insulin resistance. This leads to obesity, diabetes, heart disease, and other modern diseases.
If over-consumption of carbohydrates causes obesity and illness, the choices become protein, fat, and fiber. (There are only three macronutrients: protein, fat, and carbohydrates. Fiber is a necessary but non-nutrient element of food.)
People have forgotten the original, low-carb Weight Watchers diet. I have not; I observed family members using the diet in the 1970s. It was famous for dieters using a special scale to weigh their food.
You were required to eat a certain quantity (measured in ounces) of meat or fish per day and to eat three fruits per day. This was not optional, but required. You were allowed one-half slice of bread per day. A number of vegetables, like green beans, were “free foods” that could be eaten in unlimited quantities. Refined sugar and desserts were strictly forbidden (or “illegal”).
This diet worked, especially for men. A typical problem was losing weight too fast.
In retrospect, I see that this was indeed a sustainable way of eating. Yet once people lost weight, they tended to quit.
Weight Watchers tried very hard to address emotional eating, but I think that the missing piece was a failure to address the dieter's pre-existing nutritional deficiencies. Weight Watchers needed to add superfoods to its diet and exclude food additives.
But the company went in a different direction.
They responded to member difficulties by changing the diet to a “points system” and making sure that people felt that they could eat cake. The diet no longer worked. The company started selling frozen TV dinners filled with sugar and food additives.
The Atkins diet was explicitly about carbohydrate restriction. It was meant to be a short-term diet that shifted the body to using its own fat.
The original Atkins diet restricted carbohydrates to nearly zero for the first week. You were to gradually add carbohydrates while monitoring your body's responses.
Gary Taubes has written about the validation of the Atkins diet, both as weight loss and conceptually.
Gary Taubes: What If It's All Been a Big Fat Lie
Like Weight Watchers, the Atkins Nutritionals company changed the diet and transformed into a company that sells TV dinners and candy (“energy”) bars.
The Primal Blueprint is a popular and well-thought-out low carb high fat diet developed by Mark Sisson. It includes lifestyle and exercise recommendations.
Superfoods: Organ meats, whey protein
Website: The Primal Blueprint
The Paleo diet was developed by Loren Cordain as a modern version of what our ancestors ate in the Paleolithic era.
The Paleo Diet prohibits: refined sugar, processed food, grains, dairy, legumes, potatoes, and refined vegetable oils. It includes: meat, fish, eggs, fresh fruit and vegetables, nuts and seeds, and healthy fats. It presents itself as moderate fat level and (unscientifically and inconsistently) discourages saturated fats.
Website: The Paleo Diet
Many people have used low carb high fat diets for weight loss and blood sugar control. These diets are time-tested and there is a lot of available support. Like all diets, they are not for everyone.