When it comes to finding the best way to lose weight, it all comes down to individual preferences and metabolic needs. That’s the finding of a new study comparing three popular weight loss diets, published in the New England Journal of Medicine. But the results of the study won’t stop the diet wars from raging on. In fact, the trial, which compared a low-carb, Atkins based diet, Mediterranean style diet and a low-fat diet recommended by the American Heart Association, has left many scratching their heads.

Quick Facts about the Study 

• Conducted over a two year period with 322 moderately obese Israelis
• Eighty-six (86%) of the participants were men – it is unknown how the results apply to women. Men have more muscle mass and generally less fat than women.
• Low-Carb diet in study was “based” on Atkins diet. Contrary to recommendations typically associated with Atkins, the low-carb group was encouraged to look for vegetarian sources of protein and fat and to avoid trans fat.
• Low-fat diet and Mediterranean diet – women were restricted to 1500 calories/day, men restricted to 1800 calories/day
• Study was partially funded by  Atkins Research Foundation

 
In the study, the Mediterranean diet group (moderate fat, restricted calories) ate the most dietary fiber and as a result, experienced more favorable glucose and insulin levels. In previous studies, the Mediterranean diet has been praised for its heart health benefits, emphasizing vegetables, nuts and poultry and fish over red meat. The low-carb group (non-restricted calories) consumed the least amount of carbohydrates and largest amounts of fat, protein and cholesterol, yet saw the greatest improvement in HDL (good) cholesterol. This finding shakes the now conventional wisdom about the effects of a high-fat, high-cholesterol diet.

The scientific evidence from multiple studies point to diets high in saturated and trans fat as major contributor to the development of heart disease and stroke. Writing in a Newsweek column, Dr. Dean Ornish, M.D., who has researched and written extensively on the benefits of a low-fat diet, cautions against taking the results of the study as reason to run out and start loading up on fat.

“Your body makes HDL to remove excessive cholesterol from your blood and tissues. Not everything that raises HDL is good for you. For example, if you increase the amount of fat and cholesterol in your diet (e.g. an Atkins diet), you may increase your HDL because your body is trying to get rid of the extra fat and cholesterol by increasing HDL.”

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Dr. Ornish also takes issue with the low-fat diet followed in the study. Based on the American Heart Association guidelines at the time, the low-fat diet in the study aimed for 30% of calories from fat, 10% of calories from saturated fat and an intake of 300 mg of cholesterol per day. “The one [low-fat diet] used in the NEJM study was not very low in fat. It was based on the American Heart Association (AHA) guidelines, which I have long criticized as not being enough of a change in diet to show much benefit.

However the AHA, in a statement about the study, notes that the low-fat diet used in the study was based on recommendations issued in 2000 and that the Mediterranean diet followed in the study reflects the organizations current guidelines issued in 2006. “A range of 25-35 % for total fat consumption is suggested for most people, not just those trying to lose weight.” The AHA’s current guidelines also calls for less than 7% of calories from saturated fats and less than 1% of trans fat to be consumed daily.

So how do you make sense of all these guidelines and percentages? The bottom line is that if you need to lose weight, you have options. Despite the never-ending quest for the “best diet,” the consensus is that whether you are looking for dietary options to help with weight loss or to support your overall healthy lifestyle, foods high in saturated and trans fat should be avoided while vegetables, fruits, whole grains and healthy fats such as those from fish, nuts and olive oil are encouraged. Whether it’s called Mediterranean, AHA or by some other name, these basic guidelines form the foundation of a healthy and sensible nutritional plan that can be maintained for a lifetime.