Low-carb, high-protein diets indeed seem to be the best bet for losing weight, and will even increase your good cholesterol and reduce the fats in your blood, according to a study conducted by researchers from Ben-Gurion University of the Negev.
The study, which followed 322 workers at the Negev Nuclear Research Center in Dimona, was published recently in the Journal of the American College of Nutrition. It showed that for losing weight in the short term, which the researchers put at six months, a low-carbohydrate diet, based on meat, fish and eggs - in short, a refined version of the famous Atkins Diet - led to the highest weight loss, with an average drop of 6.4 kilograms.
The "Mediterranean" diet, which was characterized by two portions of fish a week and regular consumption of olive oil and nuts, led to an average weight loss of 4.9 kilograms over the period, while the traditional low-fat diet based on pasta, rice and potatoes led to an average weight loss of 4.7 kilos.
This difference held up over the longer term - two years - as well. Over the two years, during which many of those examined put back on some of the weight they'd lost, the low-carb diet still won out, with low-carb eaters losing an average of 4.7 kilos, while the Mediterranean eaters lost 4.4 kilos and the low-fat, high-carb dieters lost only 2.9 kilos.
The low-carb and Mediterranean diets also led to substantial improvements in blood test results, raising the subjects' HDL ("good" cholesterol ) levels, while lowering their triglyceride (fat ) levels and reducing their insulin excretion and glucose levels during a fast.
The study showed that on average, a person consumes 3.6 kilos of food a day, made up mostly of liquids (32.6 percent excluding water, which was not counted ); vegetables (18.8 percent ); fruit (17.7 percent ) milk products (9 percent ) meat (7.7 percent ) and grains and baked goods (7.1 percent ).
The three diets that were tested led to a one-kilogram reduction in the weight of the food consumed.
"The most concentrated foods, the ones that weigh the least, actually add the most calories to one's daily consumption," said Prof. Iris Shai of the International Center for Health and Nutrition at Ben-Gurion University who led the research team.
The researchers' analysis showed that the food groups that statistically predicted success in losing weight over six months were different among the three diets. In the low-carb diets, the highest losers ate more vegetables; in the Mediterranean diet, the highest losers ate more unprocessed legumes, such as chick peas, and more milk products; while for the low-fat dieters, reducing the consumption of sweets and cake were the best predictors of weight loss.
For those trying to keep weight off over the long term, all three types of dieters benefited from increasing consumption of vegetables and meat while reducing consumption of eggs, processed legumes and soft drinks.
More specifically, low-carb dieters benefited most from eating more meat and reducing consumption of drinks other than water; the Mediterraneans did best with lowering consumption of processed legumes, eggs, bread, potatoes and pasta; and low-fat dieters did best by eating more vegetables and lowering consumption of processed legumes.
"What's common to all three diets is the recommendation to dramatically increase the consumption of vegetables and reduce consumption of processed foods and snacks," Shai said. "Beyond that, it's recommended to choose different strategies in accordance with the diet that's chosen."
The BGU team's research had previously resulted in other findings. For example, in 2010, in a study published in the journal, Circulation, it was found that all three diets reduced the plaque that accumulates in blood vessels, thus reducing the risk of heart attacks and strokes.
In another study - linked to this research and conducted by Shai, along with Prof. Assaf Rudich of BGU, researchers from the nuclear research center in Dimona and from Leipzig University in Germany - it was found that the body "remembers" a diet even when the subject has lost all the weight that diet took off and starts gaining weight again.
Though both insulin and leptin - a hormone excreted by fatty tissue - starts to increase as the person gains weight, other blood markers continue to improve, preserving the medical condition of those who continue to eat healthy food, even if they gain weight.
Thus, the good HDL cholesterol continues to rise, while C-reactive protein - a marker of bodily inflammation that increases the risk of heart disease - continues to drop. This research was published in the journal, Diabetes Care.