You may have heard all the hype recently about how a new study showed that a low carb diet and a low fat diet are equally effective in helping people lose weight. These findings were published in the February 20 issue of the Journal of the American Medical Association.
But before you hit the grocery store for your favorite brand of low-fat cookies that you thought you missed so much, let’s find out the facts. This study involved over 600 adults who were between 15 and 100 pounds overweight, and they were selected to follow either a supervised low carb or low fat diet for a year. To start, they had to reduce their carb or fat intake each day to only 20 grams during the first eight weeks. After that, they could add five to 15 grams of fat or carbs back gradually. At the end of the year, both groups lost similar amounts of weight. What sets this study apart is that the participants were asked to focus on eating healthy foods, instead of a certain percentage of carbs, fat or calories. They were asked to maximize vegetable intake, minimize intake of added sugars, refined flours and trans fats and focus on minimally processed whole foods while cooking at home as much as possible. This means they were eating nutritious foods that naturally satisfied their hunger (instead of that package of low fat cookies). Think of it this way: the low fat group was told to avoid foods that may be low in fat but could be inherently high in sugar—soft drinks, juice, white bread and rice—in favor of hearty whole grains, lean meats, low-fat dairy, fresh fruits and legumes. The low carb group ate healthy fats like olive oil and avocadoes, heart-healthy salmon, eggs, cheeses, vegetables, nuts and seeds and grass-fed and pasture-raised meat and poultry.
In other words, no wonder both groups lost weight. They successfully revamped their eating habits by eating a high-quality diet that incorporates a variety of nutritious and filling whole foods.
But, this study did not test the effectiveness of a true low carb diet (or low fat diet, for that matter). By the end of the study, the low fat participants ate a diet consisting of 48% carbohydrates, 29% fat and 21% protein, and the low carb participants ate a diet consisting of 30% carbohydrates, 45% fat and 23% protein, which means the low carb participants averaged out at around 90 to 120 grams of net carbs a day, right around maintenance level for the Atkins diet. In other words, maintenance level for the Atkins diet could be considered just as effective for weight loss as a “low fat” diet even in the lifestyle phase.
While this study was too high in carbs to show the beneficial impact of an actual low carb diet (and possibly too high in fat for a traditional low fat diet), it does prove that when you limit added sugars, refined flours, trans fats and processed foods and embrace a healthy whole-food diet, you can lose weight and make lasting lifestyle changes.