Research: A portion-controlled diet Is more effective for weight loss

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Portion control actually works for weight loss.

Portion Control

Portion Control

Weight loss should be as simple as eating fewer calories ends in less weight on your torso.  Sure, it sounds as simple as not eat or drink too much, but, unfortunately, weight loss is not this simple.  This struggle is why most of the world’s population are now struggling with being overweight or obese.  In practice, it is too easy to eat or drink more than you have planned.  The question has always been how do we keep our servings eaten to the correct portion size.  

Portion sizes should be simple, but in practice, portion sizes tend to deceive us.  Some of the servings are in teaspoons while others are in cups.  Instead of trying to memorize confusing lists of ounces, cups, and tablespoons, it would be easier to buy portion-controlled servings of food that are either commercially available or premeasured by you.  With this method, you could leave the mistake of confusing portions sizes behind you for good.   Since portions are smaller than you think it should be, premeasured portions prevent you from grabbing too much when you are hungry or the infamous eating from the feed bag.  There is limited research to back up the use of portion control, and there is even less to back up portion control from commercial sources.  

The good news is that new research from 2017 looked at the use of commercial diets with controlled servings to control portion size[1]. Researchers sought to examine changes in weight and related outcomes in response to a commercial weight loss program compared to a self-directed diet in adults with overweight or obesity. Seventy-eight subjects were randomly assigned to a commercial weight loss program or a self-directed Dietary Approaches to Stop Hypertension (DASH) diet for a 16-week period.  Daily energy intake goals were 1,500 Calories per day for men and 1,200 Calories per day for women.  After 12 weeks, the study revealed that the commercial program group lost significantly more body weight than a self-directed diet.  The portion-controlled diet lost an additional 8 pounds.   Not only that, the more body fat was lost from the abdominal girth that would predispose subject to diabetes type 2 and heart disease.  Additionally, more participants in the commercial program group lost a clinically meaningful amount of weight (over 5%).

The Bottom line:  The commercial program with controlled portion sizes result in greater weight loss and improvements in body composition and weight as compared to a self-directed DASH diet over a 16-week period.  This research is extremely promising because it not only shows that portion control works.  Portion control is difficult, and I suspect the commercial diets make it easier to control portion sizes.  There are limits to this study.   Future research is warranted to understand the effects of this program on longer-term changes in body weight, in particular, weight loss maintenance, as weight regain is common following the cessation of a structured weight loss intervention.  This is good news because I wrote recently that there was limited evidence to support commercial programs.  Clearly, there is some new evidence to support them if they contain portion control.


C. M. Cook, C. N. McCormick, M. Knowles, and V. N. Kaden, “A Commercially Available Portion-Controlled Diet Program Is More Effective for Weight Loss than a Self-Directed Diet: Results from a Randomized Clinical Trial,” Front. Nutr., vol. 4, Nov. 2017 [Online]. Available: 10.3389/fnut.2017.00055″ target=”_blank” rel=”noopener noreferrer”>
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About the Author

I am a family physician who has served in the US Army. In 2016, I found myself overweight, out of shape, and unhealthy, so I made a change to improve my health. This blog is the chronology of my path to better health and what I have learned along the way.

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