What Is the Volumetrics Diet?

Volumetrics is not a new diet, but it has stood the test of time. Many people use it to lose weight and keep the pounds off. The diet is based on the premise that it’s the volume of food eaten, rather than the number of calories consumed, which leads to weight loss. When we eat more food, we experience a sense of satiety or fullness.

Barbara Rolls, PhD, is a nutrition and obesity researcher at Penn State University. She developed the Volumetrics diet based on her research and coauthored "The Ultimate Volumetrics Diet," published in 1999. Her second book, "The Volumetrics Eating Plan," was first published in 2005 and includes tips, techniques, and recipes. The 2021 U.S. News and World Report Best Diets ranks the Volumetrics Diet number 5 in Best Diets Overall and gives it an overall score of 3.8/5.

What Can You Eat?

On the Volumetrics diet, you eat low-calorie foods that fill you up, which helps you lose weight without feeling like you’re on a diet. The plan is designed so that you don't feel hungry or deprived.

You will also learn about "calorie density" on this plan. Foods recommended on the Volumetrics diet have a low energy density, so they are more filling for fewer calories. Foods that you should limit on the Volumetrics diet are energy-dense, meaning even if they have a lot of calories, you need to eat more of them to feel full. 

What You Need to Know

To follow the plan, you will eat low-calorie, high-volume foods that contain either a lot of water or a lot of fiber. Water and fiber both increase the sense of satisfaction or satiety. No food is completely banned on the Volumetrics eating plan. You can enjoy foods that are considered to be calorie-dense, like chocolate, as long as it's a treat and you stay within your daily caloric recommendations.

The recommended lifestyle changes that lead to long-term weight management include keeping an exercise and food journal and planning ahead for social situations that may throw you a curveball, such as parties. The authors also recommend that you get at least 30 minutes of exercise on most days of the week. In addition, they suggest you weigh in no more than once a week during the weight-loss phase.

Category One

The Volumetrics diet divides foods into four categories, based on their calorie density. In category one, foods are very low-density, and the diet emphasizes eating a lot of them. Category one foods include fruits and vegetables (except starchy ones), nonfat milk, and broth-based soup.

Category Two

You will eat lots of foods from category two as well, in reasonable portions. These low-density foods include grains, legumes, low-fat meats, and starchy fruits and vegetables.

Category Three

This category's medium-density foods are permitted on the Volumetrics plan, but should be consumed in moderation (small servings). These are foods that are higher in fat, refined carbohydrates, and/or sugar: Meat, cheese, French fries, bread, ice cream, and so on.

Category Four

High-density category four foods are eaten only occasionally. They are even higher in fats, carbs, and sugars than the category three foods. These include butter, nuts, oil, crackers, cookies, and candy.

Resources and Recommended Timing

Frequent eating is recommended on the Volumetrics diet—three meals and a snack or two, as long as they follow the Volumetrics principles (heavy on category one and two foods).

The Volumetrics books help you learn the calorie density of the foods you want to eat, so you can adjust the amounts accordingly. The books provide a food density list for hundreds of foods, plus a technique for figuring out the calorie density of any food using the number of calories and serving size.

The books also include a formula for you to determine how many calories to eat each day, meal plans for 1,600 and 2,000 daily calories, and lots of recipes. Plus, there's a maintenance plan to follow once you have met your goal weight, or after six months have passed.

Sample Shopping List

The Volumetrics Diet focuses on high volume, lower-calorie foods, with some higher calorie whole foods allowed in smaller quantities. As such, you will be shopping for a large amount of produce. Keep in mind that nothing is truly off-limits with the Volumetrics Diet. Since the eating plan is flexible in terms of food choices, this is not a definitive shopping list; you may find other foods that work best for you.

• Fresh fruits and vegetables with high water content (apples, tomatoes, cucumber, grapefruit, zucchini)
• Frozen fruits and vegetables (berries, cherries, peas, green beans)
• Whole grains (steel cut oats, brown rice)
• Beans and legumes (black beans, kidney beans, black-eyed peas)
• Low-fat fish (tilapia, cod, sole)
• Lean skinless protein (chicken breast, turkey breast, fish)

Sample Meal Plan

You can eat three meals plus snacks on the Volumetrics Diet. There are different meal plans for the varying calorie levels, which you can determine using the book's formula. You can modify each meal plan to your specific caloric needs. Portion sizes vary depending on calorie goals. You can also use guidelines in the book to plan your own meals.

Day 1

• Breakfast: Oatmeal with berries, almond milk, and pumpkin seeds
• Lunch: Garden salad with grilled tilapia, topped with a squeeze of lemon and drizzle of olive oil
• Dinner: Baked, skinless, chicken breast; boiled potatoes; sautéed spinach
• Snack: Low fat cottage cheese with apples and cinnamon

Day 2

• Breakfast: Boiled eggs; steamed asparagus; whole-grain toast
• Lunch: Chickpea and vegetable soups; garden salad
• Dinner: Chicken breast, mushrooms, and bell peppers in marinara sauce with black bean noodles
• Snack: Low-fat Greek yogurt with berries

Day 3

• Breakfast: Whole egg plus egg whites, scrambled; whole wheat tortilla; baby spinach; low-fat cheese
• Lunch: Tuna mixed with avocado, cucumber, and lettuce on whole-wheat bread
• Dinner: Lean grilled steak; rice pilaf; grilled mushrooms, peppers, and onions
• Snack: Chickpea hummus with carrots, grape tomatoes, and whole-grain pita bread

Pros and Cons

Pros

Nutrition

The Volumetrics plan does not exclude any foods or food groups, but it does emphasize those foods that offer nutrients and fiber without a lot of calories. So it is balanced and will allow you to get all the nutrients you need from food.

Efficacy

Research by Rolls and others shows that eating this way can help people lose weight. It is also a sustainable eating pattern that can be continued indefinitely.

Lifestyle Changes

The plan encourages regular, moderate physical activity, which is a definite plus. Many diets ignore exercise altogether, despite the fact that regular activity is a vital part of a lifestyle that leads to long-term health and permanent weight loss. Additional recommendations, such as keeping a food diary, will also help users adjust to a new lifestyle.

Cons

Time Consuming

Especially when you are new to Volumetrics, it will take time. You will need to analyze your food choices for density, keep track of what you are eating, count calories, and prepare food.

Lack of Online Support

There are a few Volumetrics apps, but none developed by the book's authors. If you want to rely on an app instead of a book to check a food's density and track your meals, you will not be able to do so easily.

Is the Volumetrics Diet a Healthy Choice for You?

The Volumetrics diet is inclusive and balanced, like other diets that encourage lifestyle change and gradual weight loss. It's not a quick fix, but a way of eating that takes some time to learn and adopt.

The food recommendations in the Volumetrics diet are consistent with the eating guidelines promoted by the U.S. Department of Agriculture (USDA). The eating plan promotes a healthy, balanced diet of fruits, vegetables, and whole grains and encourages you to limit your saturated fat intake. 

The daily calorie intakes suggested for weight loss on the Volumetrics plan (1,600 for women, 2,000 for men) are fairly sustainable for most people, but the USDA suggests your needs should be determined by your activity level, sex, and age. While the book helps you determine a smart calorie range for you, you can also do so using this calculator.

Health Benefits

Provides Vitamins, Minerals, Fiber, and Antioxidants

The Volumetrics Diet emphasizes highly nutritious foods. That makes it easier to obtain the recommended amount of vitamins, minerals, fiber, and antioxidants, all of which may help improve overall health.

Safe and Sustainable

This diet is very safe and is typically sustainable as long as it's followed carefully. It is a gradual change to a lifelong way of eating. Once users have lost the desired amount of weight, they switch to a maintenance plan that helps them keep their weight steady. Managing weight can help prevent health conditions associated with obesity.

Health Risks

There are no known health risks from this eating pattern, which is safe and flexible enough to account for allergies, sensitivities, and food preferences. However, it's always wise to check in with your doctor before undertaking a weight-loss program to make sure it is safe for you to do so.

A Word From Verywell

When the caloric guidelines and food recommendations set forth in this plan are followed correctly, this diet is both effective and nutritious. It will not bring major results very quickly but instead leads to a safe, gradual weight loss. That's ideal for long-term success—and you can continue eating this way for the long term, too.

Remember, following a long-term or short-term diet may not be necessary for you and many diets out there simply don’t work, especially long-term. While we do not endorse fad diet trends or unsustainable weight loss methods, we present the facts so you can make an informed decision that works best for your nutritional needs, genetic blueprint, budget, and goals.

If your goal is weight loss, remember that losing weight isn’t necessarily the same as being your healthiest self, and there are many other ways to pursue health. Exercise, sleep, and other lifestyle factors also play a major role in your overall health. The best diet is always the one that is balanced and fits your lifestyle.