Advocates of the South Beach diet contend that people eating a typical Western diet need to abstain from most carbohydrates at the beginning of a diet in order to break the cycle of cravings for carbohydrate foods, and to cause a significant loss of weight early in the diet.
Similar to advocates of a low-glycemic-index diet, they also claim that human physiology is not designed to tolerate the rapid and prolonged elevations in blood sugar and insulin caused by the abundance of processed, high-glycemic-index foods in the typical Western diet. Research does suggest that excessive high-glycemic-index foods, high insulin levels, and the resulting insulin resistance is associated with many health concerns, including obesity, type 2 diabetes, heart disease, and some cancers. Moreover, changing to a low-glycemic-index diet has been shown in most studies to reduce insulin resistance, help control appetite, improve weight-loss results, enhance blood sugar control in diabetics, lower blood levels of total and LDL ("bad") cholesterol, and raise blood levels of HDL ("good") cholesterol.
As do advocates of a Mediterranean-type diet, they also claim that most fats from plant sources or fish are healthy, especially when they are high in unsaturated fats that contain no trans fatty acids produced by the process of hydrogenation. These dietary fats and their food sources are considered compatible with good health and disease risk reduction. Research has found that fish, nuts, olive oil, and other foods high in unsaturated fats that are free of trans fatty acids are associated with protection from hardening of the arteries (atherosclerosis), heart disease, insulin resistance, and other health concerns.