While diet doctors everywhere were all atwitter over the FDA's first approval in 13 years of a new diet drug, lorcaserin (which is basically speed gussied up with some hormonal hunger-signal blockers) a smart bit of research was published with little fanfare in the Journal of the American Medical Association that actually provides a blueprint for how dieters can eat more effectively in order to maintain weight loss (the holy grail of big-losers everywhere.) Even better news: it doesn't require drugs or a starvation diet.
What the researchers at two of Boston's premier hospital centers--Brigham and Women's and Children's--uncovered is that
a low-glycemic-index, Mediterranean diet (with 40% of calories coming from complex, low-sugar carbohydrates; 40% from fat; 20% from protein) helps dieters keep off lost pounds
and is far healthier than either a low-fat diet (60% carbs; 20% fat; 20% protein) or an ultra-low-carb, high-protein diet like Atkins (10% carbs; 60% fat; 30% protein.)
What's exciting is the researchers--funded largely by a running shoe foundation, the New Balance Foundation for Obesity Prevention--figured out why the Mediterranean diet was best at keeping off unwanted pounds.
First, participants at the two Boston hospital centers were required to lose 10%-15% of their body weight on a calorie restricted, high protein diet. Then the experimental part of the study kicked in, with all participants placed on one of the three diets. (Participants received $500 for the initial weight loss and $2000 for completion...nice work if you can get it.) The study lasted for four years, and data was collected throughout. The length of this study adds power to the outcome.
What's unique is its focus on Reduced Energy Expenditure (REE), an adaptive mechanism triggered by weight loss.
After significant weight loss the body reduces its rate of energy expenditure (which equals less calories burned) in order to stop further weight loss. REE is an evolutionary quirk that protected hunter gatherers during lean times. But in the modern era it's a biological mechanism that's counterproductive to weight loss, making it much easier (and more likely) to regain pounds after dieting.
The clear winner was the low-glycemic index diet. Participants who followed this diet rich in healthy fats and nutrient dense, complex carbohydrates like lentils, beans, whole grains and vegetable fiber burned an extra 150 calories per day (avoiding REE) while inflammation, stress hormones, triglycerides, cholesterol levels and all other measures of good metabolic function remained normal.
The high-protein Atkins diet works for weight loss because it tricks the body into burning more calories at rest, but it appears to cause unhealthy inflammation. The key to this study was in measuring which diet burned more calories without causing any unwanted metabolic imbalances.
Both the high protein and low fat diets can lead to health issues. While people on the high-protein diet burned more calories overall (they burned 300 additional calories per day), this revved metabolism came at a cost: it increased levels of the stress hormone cortisol and of the inflammatory molecule, C-reactive protein (CRP). Increased cortisol puts additional stress on the nervous system and leads to weight retention (counteracting the additional calories burned.) Elevated CRP is associated with an elevated risk of a host of inflammatory conditions including diabetes and heart disease. The low fat diet yielded no benefits in terms of calories burned, it resulted in elevated artery clogging triglycerides (a type of fat the body can use for energy) and a decrease in good cholesterol--a lose lose situation.
To keep off pounds eat a diet rich in complex carbohydrates, healthy, lean protein and healthy, mono-unsaturated fats like olive oil and avocados. One easy way to do this would be to move to Sardinia, where this is the local diet and--not coincidentally--it's home to the world's highest concentration of men living past their hundredth birthday.