This Popular Diet Is Supposed to Help You Lose Weight by Eating More. Here's How It Works
This top-ranked diet is easy to follow and backed by research.
Conventional wisdom has it that to lose weight, you have to eat less. But that’s absolutely not the case, and one top-ranked diets proves it. The Volumetrics diet, developed by Penn State professor and researcher Barbara Rolls, is all about filling up by eating a larger volume of food, while simultaneously slimming down.
The concept might sound too good to be true, but Volumetrics is backed by science, and it has a proven track record of helping people shed pounds. It even tied for number six on U.S. News and World Report's latest list of the best diets overall. Here's what this weight-loss plan is all about, how to follow it, and a few challenges that you might come across if you give it a go.
How to follow Volumetrics
Though no foods are off-limits, the idea behind Volumetrics is to focus on "energy density," which means the number of calories in a given portion of food. Foods with high energy density pack more calories for a relatively small portion, whereas low energy density foods are low in calories for a larger volume.
On the plan, some low energy density foods can be consumed at any time. These include water-rich, non-starchy veggies (like tomatoes and mushrooms) and broth-based soups. Whole grains, lean proteins, beans and lentils, and low-fat dairy products are allowed in moderate portions. Breads, cheeses, and higher-fat meats are limited to small portions. And fried foods, sweet treats, and candy are allowed, but sparingly.
Rather than laying out exactly what to eat, Volumetrics gives you the ability to choose your menu. But when you select high energy density foods, your portions must shrink. The point is to fill up on low energy density foods, which are generally healthier and more nutrient-rich—such as salads, broccoli, and fresh fruit.
For example, you can eat a cup of seedless grapes, about the size of a tennis ball, for the same number of calories as two small cookies. Or for the same number of calories in 20 mini pretzels, you can eat about three and a half cups of popcorn, or an entire cucumber and two tablespoons of hummus.
Physical activity is also encouraged, starting with an additional 150 steps per day, with a goal of hitting 10,000 steps daily per your fitness tracker or pedometer. Keeping a food diary is also helpful.
Why Volumetrics can work
The plan estimates a weight loss of one to two pounds per week, and it’s research-backed. In fact, dozens of studies, including some conducted by Rolls, support the approach, in terms of weight-loss outcomes.
There are key positives to this approach. For many people, placing certain foods completely off-limits backfires; it ultimately leads to rebound binge eating or reverting back to old habits. I've long incorporated aspects of this plan with my private practice clients, particularly those who feel they need larger portions in order to feel full. In my experience, understanding how to build in can’t-live-without splurges in a balanced way better supports sustainability. The plan also emphasizes eating fresh, whole foods, as well as home cooking.
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The drawbacks of Volumetrics
Many of my clients tell me that focusing on calories increases their anxiety, or it can trigger a preoccupation with numbers. Also, the premise doesn’t always hold true. For example, I often feel far more satisfied by a quarter cup of nuts, a few tablespoons of nut butter, half of an avocado, or a few squares of dark chocolate than a larger volume of popcorn. In other words, volume alone, or even fullness, does not always correlate with satisfaction.
Another thing is, the plan may encourage filling up on low-calorie, highly processed “diet” foods, including those made with faux sweeteners. Not only are these products devoid of nutrients, but the artificial ingredients can wreak havoc with appetite and immunity.
Should you go on it?
There is a lot to like about this approach. If you try it, focus on upping your portions of non-starchy veggies first, balanced with lean protein, healthful fat, and a small portion of whole, fiber-rich carbs. Use the Volumetrics technique to become more choosey about snacks and treats, but always listen to your body, and focus on all natural, clean ingredient foods.
Cynthia Sass, MPH, RD, is Health's contributing nutrition editor, a New York Times best-selling author, and a consultant for the New York Yankees and Brooklyn Nets.