Developed by Barbara Rolls, professor of nutritional science at Penn State University, the Volumetrics Diet is an eating plan designed to help you effortlessly lose weight without a feeling of restriction or deprivation. The diet is based on the belief that people tend to consume the same amount of food every day, regardless of the caloric density of the foods consumed. With this in mind, Rolls encourages primarily consuming foods that are low in calories, but high in nutrition, water, and fiber to help keep you full and satisfied.
Category 1 foods (very low-density) include non-starchy fruits and vegetables (think spinach, broccoli, tomatoes, carrots, apples, and oranges), non-fat milk, and broth based soups. These are the foods you should focus on consuming the most of. They are filled with vitamins, minerals, and other important nutrients, plus are very expansive and will provide the sensation of fullness with fewer calories.
Category 2 foods (low-density) include starchy fruits and vegetables such as potatoes and bananas, lean proteins, grains, and legumes. These still have a lot of nutritional value, but tend to be slightly higher in calories. One cup of oatmeal for example (a category 2 food) contains 158 calories and 4 grams of fiber, while 1 cup of grated carrots (a category 1 food) contains only 45 calories and 3 grams of fiber.
Category 3 foods (medium-density) include bread products, cheeses, and higher fat meats such as beef or salmon. Similar to category 2 foods, these foods still contain valuable nutrients, but they are even higher in calories.
And category 4 foods (high-density) include nuts, fried foods, candy, desserts, and other fatty foods. Think of these as treats. There is no need to completely eliminate them from your diet, but they should be consumed only occasionally and in minimal amounts – preferable after consuming a meal rich in category 1 and 2 foods so that you are already pretty full and are less likely to overeat any of the category 4 foods.
In her book, The Ultimate Volumetrics Diet, you’ll learn how to easily identify each type of food so that you can start building a customized weight loss diet based on your personal food preferences. Dieters are encouraged to fill their plate primarily with category 1 and to stick to 3 meals, 2 snacks, and a dessert each day. According to Rolls, “Volumetrics is about being educated for life to make decisions about your eating.” Once you learn to simply choose foods that support weight loss, eating healthy will become a habit – making it easy to lose and maintain weight. There are no membership fees but in order to gain a full grasp on what the diet is about you should purchase the book for $11.
Although there hasn’t been a specific Volumetrics Diet review, per se, there has been plenty of research indicating that a diet rich in low calorie foods (otherwise known as “low-energy-dense” foods) is ideal for weight loss.
In 2007, the American Journal of Clinical Nutrition published a study in which 97 obese women were assigned to either a low-fat diet or a low-energy-dense diet that prioritized fruit and vegetable consumption. After a year, the fruit and vegetable dieters lost more weight (14 pounds on average) than those on a low-fat diet (11 pounds on average).
A study published by Obesity Research in 2005 found similar results. This study, co-authored by Barbara Rolls, divided 200 overweight or obese adults into one of four groups. Group 1 received one serving of soup a day, Group 2 received two servings of soup, Group 3 received two daily snacks such as crackers and pretzels, and Group 4 (the comparison group) developed their own low-energy-dense diet without any restriction. (Soups are a major component of the Volumetrics Diet since they are generally lower in calories but contain a lot of water to help keep you full). Since Group 4 consumed a self-constructed low-energy-dense diet these dieters were most similar to anyone following the Volumetrics Diet. At the end of one year, all dieters had lost fairly substantial amounts of weight – indicating that a diet based on low-energy-dense foods is effective for weight loss. Furthermore, out of the four groups, the group 4 dieters lost the most weight (17 pounds on average!) pointing towards the effectiveness of a self-constructed diet that follows the Volumetrics principles.
Another study, which essentially operates as a Volumetrics Diet Review, was released in the European Journal of Nutrition in 2016. This study, which again was co-authored by Rolls, observed the food-consumption patterns of over 9,500 adults. Researchers discovered that those who ate a higher portion of low- and very-low-energy-dense foods (synonymous to category 1 and 2 foods from the Volumetrics Diet) had lower BMIs, smaller waists, and were less likely to be obese.
The Volumetrics Diet is easy to follow. It can be tailored to your own food preferences and there are no hard and fast food restrictions. You can even eat out! As long as you are ordering foods that are primarily category 1 and 2. Because category 1 and 2 foods are filled with water and fiber you will also be full and satisfied after each meal on this diet.
Even though eating out is allowed, home cooked meals are always better when dieting. Meal planning, grocery shopping, and meal preparation can be time consuming processes. Additionally, for people who have trouble listening to their body’s signals, it can be difficult to know when you are truly satisfied given that the Volumetrics Diet plan doesn’t provide any rules in regard to how many calories you should be consuming at each meal.
It’s easily customizable and teaches you the skills you need to develop healthy eating habits for life. Since no foods are off limits, it also prevents dieters from feeling deprived while still keeping them full throughout the day.
If you are used to eating a lot of simple carbs and sugary foods, you may find yourself still craving these treats when you first go on the Volumetrics Diet. MealEnders can serve as a support to help you avoid indulging in too many category 3 or 4 foods while your taste buds adjust to consuming a primarily fruit- and vegetable-based diet.
The best way to get an understanding of what this diet is all about is to purchase the book. It’s a mere $11 off Amazon for a new copy or as little as $3 if you buy it used.