Does It Work?
While the hook of Volumetrics is clever, it boils down to the sensible diet that any nutritionist would recommend: lower calories, lower fat, with lots of vegetables and fruits.
Rolls has excellent credentials. She's a professor of nutrition and directs the Laboratory for the Study of Human Ingestive Behavior at The Pennsylvania State University. She has also written more than 200 research articles. Volumetrics is largely based on the work done in her lab.
Level of Effort: Low
Volumetrics is a very flexible plan. Recognizing when you're full and making smart choices about the food you eat will make a big difference. If you eat for other reasons -- like when you're stressed or bored -- you'll need new ways to handle those feelings, or else you might keep eating after you're full.
Limitations: You'll need to keep an eye on the energy density of the foods you choose. For instance, for the calories of a big bowl of soup, you could have only one-sixth of a cheeseburger. The choice is up to you: Which would you rather have, and would you be able to stop after just a nibble or two if you chose the cheeseburger? If you follow the recipes, it will take time to prepare meals and to calculate energy density.
Cooking and shopping: Your grocery shopping should be easy on this plan. Rolls's books include recipes, including many for foods with a lot of water -- like soups, casseroles, stews, and fruit-based desserts. The recipes also cut down on oil, butter, eggs, and cream, and use skim milk, egg whites, yogurt, and applesauce instead.
In-person meetings: No.
Exercise: You’ll start by adding 150 steps a day to your routine, using a pedometer. The first goal is reaching an extra 1,000 steps by the end of the week. The ultimate goal is to log 10,000 steps a day.
Does It Allow for Dietary Restrictions or Preferences?
The plan is flexible enough for vegetarians, vegans, and those who need to restrict salt and fat.
What Else You Should Know
Cost: None beyond your food shopping.
Support: This is a diet you do on your own.