There are 3 main types of intermittent fasting:
This is the method that has been the most studied, has the best long-term adherence rate and seems the most promising. It allows the body to return to a normal circadian rhythm to help normalize metabolic processes. On the other hand, it does not take into account the quality or composition of the diet. There is a lack of studies to confirm the optimal timing of food intake. We notice that insulin sensitivity, beta cell responsiveness, the thermic effect of food and fatty acid oxidation are all higher in the morning than at the end of the day, suggesting that metabolism is optimized for food intake in the morning. However, fasting later in the day may be less convenient and more difficult to do.
Studies show that intermittent fasting has effects comparable to a traditional diet with caloric restriction on weight loss. The weight loss associated with intermittent fasting seems to be caused by the fact that it decreases the opportunity to eat, which decreases the total amount of calories consumed per day. There is a risk of loss of muscle mass, especially if the person does not exercise, does not consume enough protein, or does not distribute their protein intake optimally throughout the day.
Studies show that intermittent fasting can improve the lipid profile (total cholesterol, HDL, LDL, and triglycerides) over a period of 6 to 24 weeks, but more studies are needed.
The Ornish diet was created by Dean Ornish, a professor of medicine at the University of California. This diet includes recommendations on nutrition but also on physical activity, stress management and social support. The goal of this diet is not only weight loss but also an improvement in overall health. It is very low in fat (less than 10% of total energy intake, no added fat allowed) and very high in carbohydrates (70 to 75% of total energy intake). It mainly includes plant based whole foods, but low-fat dairy products, egg whites, and fish are also permitted.
The Ornish diet has bene shown to be beneficial for heart health. However, it is difficult to follow in the long term due to the restriction of fats. As fat intake is very low, it is important to ensure that the fats ingested are of good quality and provide the necessary essential fatty acids for the body.