Volumetrics is a very popular and effective diet and among the most successful book-based diets available. A 2007 report by Consumer Reports found Volumetrics yielded the best weight loss of eight diets studied.
Based on research conducted by nutritionist Barbara Rolls, Ph.D. a professor at Penn State University, this popular diet is designed to maximize the amount of food per calorie. In other words, it aims for foods with low energy density, mainly those with a lot of water, so you can eat a large volume of food and feel full without consuming lots of calories. The main ways of accomplishing the volumetrics approach is using reduced-fat products, considerable low calorie veggies, and low-fat cooking techniques.
Dr Rolls asserts that by following Volumetrics, you can eat up to 800 calories less than normal, yet still feel full and not notice that you were even on a diet. The average calorie intake on the diet is 1500 if you follow it precisely, but the diet doesn't emphasize this sort of precision--if you buy the right sort of low-energy density foods, you should be able to eat until you're full and not consume too many calories.
Rather than learning calorie density numbers, you only have to become acquainted with four categories to keep things simple. These categories range from the low Category 1 (green beans, celery, lettuce etc.) to Category 2 (olives, ketchup, rice etc.), to category 3 (pretzels, raisins, oil packed tuna etc.), and finally category 4 (high energy dense foods like bacon, butter, nuts etc.). You can then mix large amounts of low density foods with some higher ones.
The Volumetrics Eating Plan contains a comprehensive guide to good nutrition and a clear explanation of the science of satiety which is so key to the diet's method. The book includes forms for charting one's daily food intake and weight-loss progress, as well as 120+ tempting recipes for the likes of Risotto Primavera and Chicken Fajita Pizza. Surprisingly, despite the diet's popularity over the decade, the book doesn't have much in the way of success stories or before/after photos--for dieters who need that sort of inspiration, you may want to look elsewhere, but for most people this shouldn't be an issue.
We believe Volumetrics is an excellent diet, but by no means perfect--for instance we have some issue with the low fat guidelines, as some late 2009 research observes that dieters lose more weight having full fat dairy products, only smaller portions of them. The reasons aren't entirely clear, but the data is from proper clinical trials, so we have become wary of diets prescribing large-scale consumption of low-fat dairy products.
Menu: As mentioned, the menu consists of low calorie density foods, so lots of fruits and veggies, which can be a bit more expensive than standard processed foods. One excellent tactic Dr. Rolls emphasizes is having a first course for dinner of a broth based soup (not a calorific creamy one!) or salad to take the edge off hunger before the main course, but these do tend to be rather inexpensive.
Of course, with more of these whole food ingredients, you will spend more prep time on this diet than many others, and this is one area where the diet has drawn complaint. If you don't have a lot of time for food preparation, this diet may be difficult to stick with.
Prices: The Volumetrics book retails for $16, but you can get it much cheaper on Amazon for around $7.
This diet originated in 2000 with The Volumetrics Weight-Control Plan, but the latest 2007 book, The Volumetrics Eating Plan: Techniques and Recipes for Feeling Full on Fewer Calories, goes into more details and take advantage of several years of dieters' experience, so we recommend reading it instead of the original.