In a toast to Mediterranean diet, a study by researchers of the University of California, San Diego School of Medicine proves that weight loss programs that provide healthy fats, such as olive oil in the Arab diet, or a low-fat, high-carbohydrate diet have similar impacts on pound-shedding.
To be precise, the researchers hit upon a meal plan rich in walnuts, which are high in polyunsaturated fats, has a significant impact on lipid levels for women, especially those who are insulin-resistant.
In the United States, 28 percent of adults over 40 of age use lipid-lowering drugs to fight high cholesterol levels. Lifestyle changes that promote weight loss and reducing consumption of saturated fat have been mushrooming to fight “bad” cholesterol, but a question persisted: Should consumers reduce fat intake by replacing with carbohydrates or substitute unsaturated fats for saturated fats?
“Many diets have said it is okay to eat healthy fats and emphasize olive and canola oils,” said Cheryl Rock, the lead researcher of the study, whose paper was published in the Journal of the American Heart Association. “What we found is that a diet high in healthy oils did lower lipids, but it also lowered both good and bad cholesterol.”
They have studied overweight women in a one-year behavioral weight loss program and randomly assigned to one of three diets — low-fat and high-carbohydrate; low-carbohydrate and high-fat; or a walnut-rich, high-fat and low-carbohydrate diet.
The findings showed that all three dietary plans promoted similar weight loss. Insulin-sensitive women lost the most weight with a low-fat diet but it failed to reduce lipid levels. For them, the walnut-rich diet had the most impact on cholesterol levels by decreasing low-density lipoprotein (LDL), or bad cholesterol, and increasing beneficial high-density lipoprotein (HDL).
The high-fat, low-carb group, which consumed monounsaturated fats, did not yield same results as the walnut-rich diet, which featured polyunsaturated fatty acids. After six months, the average weight loss was almost 8 percent among all groups.
“This weight loss may not put these women at their ideal weight, but it made a significant reduction in their risk of cardiovascular and other diseases,” said Rock. “This level of weight loss is achievable and can have a dramatic impact on their quality of life.”
Insulin sensitivity was assessed since overweight people usually have some degree of insulin resistance. Higher amounts of insulin usually cause cells to lose their ability to regulate growth, a precursor to cancer.
“Diet composition impacts lipid levels, but the critical factor to lose weight continues to be to burn more calories than you consume,” said Rock.
A recent Harvard study suggested that people who replace saturated fats with polyunsaturated fats may live longer and have a lower risk of heart disease. Last year, an Indian-origin researcher Abha Chauhan from the New York State Institute for Basic Research in Developmental Disabilities (IBR) found that a walnut-enriched diet daily helps reduce the risk of Alzheimer’s disease.
The high antioxidant content of walnuts (3.7 mmol/ounce) may have been a contributing factor in protecting the mouse’s brain from the degeneration typically seen in Alzheimer’s disease, her study suggested. Oxidative stress and inflammation are two main features in the Alzheimer’s disease. Her study was published in the Journal of Alzheimer’s Disease.