Diet Reviews from a Registered Dietitian: Volumetrics




You can find the book, HERE on amazon. The basic premise of this diet is that lower calorie foods like vegetables require a higher volume to equal the same number of calories as something higher calorie, like cheese or concentrated sweets (desserts). It’s a substitution based diet, centered around the idea that some foods will keep you fuller longer and provide a more complete nutritive profile than others. This is the foundation of Dr Rolls’ research in ingestive behavior at The Pennsylvania State University, where she is a professor.

Photo taken from “The Ultimate Volumetrics Diet” by Barbara Rolls, PhD.


The book is broken into multiple sections, the beginning focuses on the basics, like calorie density, which is important because it is the foundation of the entire diet. She then moves in to portion sizing, building your meals, balance of macronutrients (protein, carbohydrates, and fat). She has a special sections on sugar, liquid calories, eating away from home, environmental cues, and maintaining the “volumetrics” lifestyle. This comprises about half of the book (166 pages).

Each section has a sort of “NOTES” section where she has key points and additional information. There is a very good section on the difference between glycemic index and glycemic load, and caloric density. She also has several notes where she focuses on “complete” foods, and how you shouldn’t focus too hard on any one component, like carbohydrates, or fat, but take the whole of nutritional value into consideration. This is something I really liked about this book.

The final portion of the book consists of recipes where she has lowered the calorie count of things like banana bread, muffins, etc. The sections are separated by type of meal, such as breakfast or dinner, and then by type of food, such as soups or sandwiches.


I personally found it enjoyable to go through the different recipes, but I’ve also decided to spend my entire life studying food and metabolism, so I’m likely biased. I’m also a scientist, so tedium is completely fine with me. Because of working in this field for 10+ years, I should mention that I know Barbara, and many of the graduate students who came up with the recipes included in this book (and tried them in their experimental phase).

The recipes include pictures of the finished product, and how it compares to the original recipe you’re likely to find on Pinterest (in much larger portions). Most of the ingredients are easily found from your local supermarket and she gives tips on using frozen fruit and vegetables when appropriate, to make each dish more economical.

Photo taken from the recipes chapter of “The Ultimate Volumetrics Diet” by Barbara Rolls, PhD.


The book also includes an appendix with helpful references for food lists, food group serving sizes, and cooking conversion charts.


Since increasing the consumption of vegetables is one of the core principles of this book, I think including more information on strategies to actually accomplish this would be very beneficial. Much of the research from the Rolls lab focuses on children and preschoolers, but she has also completed work increasing consumption in adults as well (see references below for links to the original research). One strategy is to increase the variety of vegetables. Don’t just offer broccoli or lettuce, but instead include a mixture of different vegetables to breakup the plate.

She also has published that there is a reduction in caloric intake when you serve a meal on a smaller plate, but that this reduction isn’t significant and does not actually impact overall caloric consumption. She has also published articles about salad and noncaloric beverage (water) consumption prior to a meal. Though I do have some problems with the controls for the self-served salad articles, because of working in the clinic with actual patients attempting to lose weight.

She also has a few reviews on obesity and ingestive behavior as a whole, which I would also recommend as future reading.


I read through some of the lower ratings on amazon and other sites that sell the book, and the most common criticism is that the content is dry and too complex.  Several also mentioned that it should have been a summary or a simple “do this and lose weight” or “eat this not that,” which they would have preferred. I personally think it’s good that Rolls included the scientific principles behind her diet, as well as the basics so you can modify your own recipes and not rely on only those included in this or her two other books.

Some of the recipe comparisons aren’t really fair. For example, in one of the recipes they compare a tuna salad wrap, with their substitution, a tuna apple salad sandwich. These aren’t really equivalent. The filling is similar, but if I wanted a wrap I wouldn’t be happy with this. A couple of my favorites are the Crab-Asparagus Quiche and Alex’s Three Layer Carrot Cake.

Several people mentioned they didn’t think there were enough recipes, but this is a diet book, not a cookbook. I do think they could have increased the number by decreasing the number of full page photos within the recipes section, but overall I liked the format of the book.


Concept clarity 

I think she does a good job explaining the principles behind volumetrics and substitution dieting. She also provides a clear basis as to why the diet works, backed by peer reviewed journal citations.

Potential health concerns


Would I recommend this diet? 

Yes. This diet promotes eating a variety of foods and doesn’t omit any specific macro or micronutrient. If a diet omits or villainizes a particular food, it’s most likely not a diet you can actually maintain weight loss through, or is potentially causing an unsafe quick drop in weight. Doing this often means the diet isn’t sustainable over time. This diet teaches balance and portion sizes, both things I find very important to healthful living.


Meengs J, Roe L, & Rolls B (2012), “Vegetable variety: an effective strategy to increase vegetable intake in adults.” Journal of the Academy of Nutrition and Dietetics, 112(8); 1211-1215.

Rolls B, Roe L, Halverson K, & Meengs J (2007), “Using a smaller plate did not reduce energy intake at meals.Appetite, 49(3); 652-660.



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s