A widely publicized study out this week in the New England Journal of Medicine shows that there is virtually no difference between low-carb, low-fat, high-carb or high-protein diets when it comes to weight loss. I don’t often like to toot my own horn, but if you read my post on Monday about the Top 10 Food Facts Everyone Should Know (see point #10), then this was not news to you.
For several years now data has been accumulating that the relative composition of different macronutrients (fat, carbs, protein) in your diet has little to no effect on long-term weight loss. What makes this study stand out from the pack is how well it was designed.
This was the largest, longest run study of this kind ever conducted, including nearly 650 over weight individuals of diverse racial, socioeconomic, geographic and education backgrounds. The participants were highly motivated to lose weight and were given detailed instructions on why their assigned diet was considered an effective weight loss strategy (this was to remove bias caused by the media about popular diets).
For you carbophobes out there, the importance of dietary carbohydrates was addressed directly. The amount of carbohydrates in the different diets varied from 35% (very low) to 65% (very high). All participants, including those on the high-carb diet, were instructed to choose foods that had lower glycemic index. Carbohydrate composition had no significant effect on long-term weight loss.
All subjects received substantial behavioral therapy to help them meet their goals, and detailed measurements of health and weight loss were collected from each individual throughout the study. The participants were told to keep food journals and use online support provided, as well as weekly dietary counseling.
Importantly, all the diets resulted in similar calorie deficiencies to promote weight loss. Not surprisingly, after 6 months all the participants had lost a substantial amount of weight, but after 1 year had gained about half of it back. During the final year the subjects had more difficulty sticking to their assigned diets, particularly those assigned the most extreme regimens (very low-fat or high-protein).
Regardless of diet, all participants experienced similar, modest (5% body weight reduction), but clinically relevant weight loss that is mainly attributed to a reduction in calories.
Interestingly, the measure that best correlated with weight loss success was attendance at the dietary counseling sessions.
Since the study is over can we now assume that many of these participants have gone back to their old eating habits? I would bet yes.
What can we take away from this study?
You can lose weight on any diet, but for most people it is very difficult and not sustained. This is because cutting calories is very tough for most people.
This study also suggests that losing weight with standard diets is very difficult and, in most cases, only moderately helpful. It seems future research should focus on how to increase adherence to a lower calorie diet. Gaming the system by manipulating macronutrient composition doesn’t seem to be working.
Why you should focus on whole foods, not nutrients
Another thing we can take from this study is that if weight loss is your goal, calories are what count. (Some of my friends responded to this finding brilliantly: “DUH.”) The nice thing about a diet based primarily on vegetables is that lowering caloric intake is relatively easy. As long as some effort is made to achieve a balanced diet (enough plant protein and fats), satisfaction after a meal can be attained with far fewer calories.
Vegetables are very bulky, highly nutritious and have very few calories. It’s not easy to gain weight when you eat kale, beans and brown rice for dinner.
Like I explained a few weeks ago, since I have focused on health (rather than weight) and a vegetable-based (rather than macronutrient-based) diet, I have lost weight effortlessly. I am also less stressed about food in general, and have completely lost my old cravings for sugar and fat.
Best of all, I do not feel like I have given up anything whatsoever. In fact I would argue I have gained the freedom to eat what I want, whenever I want it. And the food I eat is much more satisfying and delicious. I guarantee you this tagine tasted better than any Atkins bar, rice cake or BigMac.
My life now is much more delicious.
Are you ready to give up diets and focus on health?