The Journal of the American Medical Association just published a two-year diet study that I think is well worth looking at–and please remember it the next time you read about how the seriously overweight can’t lose weight and keep it off without bariatric surgery or drugs because they’re programmed by their genes to be obese. What I especially liked about this study was that rather than focusing on gimmicky diets that call for nearly altogether cutting out some food group (e.g. carbs or fat), or loading up on some type of food (e.g. dairy, as pushed in another recently published study getting some press), or pushing significant calorie deprivation, it instead focused on a “behavioral” approach–that is, in educating participants in how to establish healthier, sensible, sustainable eating and exercise habits, and in providing ongoing support to encourage them to stick with the program. It was also a randomized controlled trial–the obese women who participated were randomly assigned to a “normal care” group that got fairly minimal support, or one of two groups that got much higher levels of support as follows:
The diet component of the program consisted of a nutritionally adequate, low-fat (20%-30% of energy), reduced-energy diet (typically 1200-2000 kcal/d) that included prepackaged prepared food items with increased amounts of vegetables and fruits to reduce the energy density of the diet. The approach was tailored so that participants could choose regular foods when preferred. Participants were encouraged during the initial period to follow a menu plan with prepackaged foods, which would provide 42% to 68% of energy for those who choose not to deviate from the plan. Regular foods, such as vegetables, fruit, cereal or grain products, low-fat dairy products, lean meat or the equivalent, and unsaturated fat sources were recommended to achieve the total prescribed energy intake. Over time, participants were transitioned to a meal plan based mainly on food not provided by the commercial program, although participants could choose to include 1 prepackaged meal per day during weight loss maintenance. Prepared foods and counselors were provided by Jenny Craig Inc (Carlsbad, California).
Increased physical activity was another program component; the goal was 30 minutes of physical activity on 5 or more days per week. Program material and counseling addressed attitudes about weight, food, and physical activity and included recipes and guidance for eating in restaurants, CDs and DVDs to increase physical activity, and online tools and support.
And what do you know, the participants who got the real treatments took off weight and by the end of the two years had kept it off.
By study end, more than half in either intervention group….had a weight loss of at least 5% compared with 29%…of usual care participants…. More than twice the proportion of participants in the center-based and telephone-based intervention groups compared with participants in the usual care group…had a weight loss of 10% or more of baseline weight at 24 months….
As with all diet studies, there’s plenty to be wary of, too. It was funded (but not run) by for-profit weight-loss-program company Jenny Craig, which also supplied pre-packaged meals for the studies, and bias toward the funders may well have crept in there somewhere. Two years is typically taken as a standard for proof that a diet intervention helps keep weight off, but obviously it doesn’t necessarily tell you how the participants will fare in the next two, or ten or forty years, and weight-losers, like smokers, need to be in it for the long haul in order to really raise their chances of having a long, healthy life, not just long enough to look good for their high-school reunion. The reliance on free pre-packaged food is a somewhat unrealistic model for the real world–though not completely unrealistic if we as a nation start getting more serious, as we should, about helping the obese get healthier. The treatment participants got $25 for showing up for clinic visits–getting paid to lose weight is a hot idea these days, but I don’t think smallish payments make a big difference over the long term and fear it just confuses the issue. As the study authors themselves point out, one always has to wonder if the people who participate in a diet study are representative of the population, for example in terms of level of motivation and commitment. But on the whole, I thought the diet interventions were smart, and doable on a large scale in the real world, and it was great to see them produce these impressive results in what seems a relatively careful study.
It also didn’t surprise me in the least–behavioral approaches to weight loss, including Weight Watchers, have been doing pretty well in studies on a fairly consistent basis for decades, unlike most other approaches. So let’s support more people who need to lose weight to be healthy in eschewing gimmicky and unsustainable diets, and in ignoring the toxic claims that they’re genetically incapable of benefiting from any non-surgical, non-pharmaceutical intervention, and instead make it easier for them to get access to comprehensive behaviorally oriented weight-loss programs designed to take modest amounts of weight off gradually, comfortably and forever.