I wanted to take a moment to highlight a new study that was released last week in The Journal of the American Medical Association (JAMA) that challenges the traditional notion that weight loss is only possible through calorie reduction (i.e., counting or restricting the number of calories you eat). In the DIETFITS study, researchers found that participants who cut back on added sugar, refined grains and highly processed foods while focusing on eating plenty of vegetables and whole foods — without counting calories or limiting portion sizes — lost significant amounts of weight over the course of a year.
The study was a randomized clinical trial that included 609 overweight adults, who were assigned to either a healthy low fat (HLF) or a healthy low carb (HLC) diet group. Members of both groups attended classes with dietitians where they were educated about eating nutrient-dense, minimally processed whole foods, preferably cooked at home. A key difference in this study is that it did not set restrictive limits on the amount of carbohydrates, fats or calories that participants could eat. Rather, the researchers emphasized that participants focus on eating whole or “real” foods and as much as they needed to avoid feeling hungry. The emphasis was on the quality, not quantity, of food that was consumed.
The researchers also wanted to test the hypothesis that some people are predisposed to do better on one diet over the other depending on their genetics and their ability to metabolize carbs and fat. A growing number of services offer people personalized nutrition advice tailored to their genotypes. (See this previous post about my experience with one of these genetic testing services). Somewhat surprisingly, they found that participants’ genotypes did not appear to influence their responses to the diets. This is something to keep in mind if you are thinking about pursuing genetic testing for guidance on nutrition.
The general outcome of the study was that after one year of focusing on food quality, not calories, both groups lost substantial amounts of weight. On average, the members of the low-carb group lost about 13 pounds, while those in the low-fat group lost almost 12 pounds. The good news is both groups also saw other health improvements such as reductions in their waist sizes, body fat percentage, and blood sugar levels.
It is important to note that there was variability among the participants – some people gained weight, and some lost as much as 50 to 60 pounds. One key finding though is that the people who lost the most weight reported that the study had “changed their relationship with food.” For example, they no longer ate in their cars or in front of the television. They also started cooking more at home and sitting down to eat dinner with their families. To me, this demonstrates that how we eat is just as important as what we eat.
As with any research study, there are limitations. This was only one study involving a relatively small number of participants. Repeat studies with larger sample sizes should be conducted to see if results can be replicated. This study also just focused on initial weight loss. Maintaining weight loss can be as hard, if not harder, than losing the weight in the first place. Future studies may want to follow participants over time to see if they can maintain a healthy weight following the same approach of focusing on quality, not quantity.
I hope that this study is just one of many that will show that traditional dieting, where people make themselves miserable by counting or restricting calories, is not the best or most sustainable way to attain and maintain weight loss. Rather, if we shift our focus to the quality of foods we eat and take time to enjoy and savor our meals, we will change our relationship with food and reap the many health benefits that come along with eating a well-balanced diet.