How to Use Vegetables to Help Cut Calories: The Research

You know vegetables are low in calories, but what surprises many people – until they stop and think about the logic – is that simply adding vegetables to your current diet will not necessarily help you lose weight. You’ll get more nutrients, fiber and protective plant compounds. But the way vegetables help you lose weight is when you substitute them for something you’re currently eating that’s higher in calories. This is how you can use calorie density to help reach and maintain a healthy weight.

In the first portion of my video interview with Barbara Rolls, PhD, she discussed the studies showing how calorie density plays a role in weight management. In this section, Dr. Rolls goes into more detail about specific research-tested strategies for how to use vegetables to successfully reduce calorie density so you can cut calories without going hungry, and do it in a way that gives you a balanced diet, too. Dr. Rolls is chair of the department of nutritional sciences at Penn State University and a pioneer in calorie density research.

(After you watch the video, read on for practical examples and tips!)

Research-tested Strategies
Dr. Rolls and other researchers working on calorie density have identified several different ways that you can incorporate more vegetables in your meals to lower calorie density and cut your overall calories. Try them all, and see which ones work best for you in various circumstances.

Give vegetables a larger role in mixed dishes.
Boost vegetables from minor player to star feature, or add vegetables to a rice, pasta, chicken, seafood, meat or bean dish that originally had none. For example:

• A chicken-broccoli stir-fry in Dr. Roll’s Ultimate Volumetrics Diet book includes about 2 cups of broccoli, carrots and water chestnuts per serving. That’s more vegetables than you get in a typical Chinese restaurant take-out dish.
• Greek-style scallops in the American Institute for Cancer Research cookbook, The New American Plate, deliciously include onion, mushrooms and tomatoes, providing about a cup of vegetables per person.
• When I make vegetable lasagne, chili, or almost any soup, I automatically adjust vegetable amounts to provide anywhere from one to two cups of vegetables per person. Sometimes that means simply boosting the amounts of vegetables in a recipe; sometimes I use my creativity and come up with additional vegetables that I think will add a nice dimension. It’s fun! If it’s a meat-heavy dish, I cut down the meat or poultry as I boost vegetables, or I might switch out the meat completely and add black beans, garbanzo beans, lentils or some other legume as the protein in the dish.

Give vegetables a larger role as unseen supporting cast
If you miss the luscious thick texture of sauces and soups as you’ve been cutting back on fat and cream sauces, you may especially love what adding puréed vegetables does to a mixed dish. In our interview, Dr. Rolls notes that some people are opposed to a “stealth approach” to adding vegetables to dishes, and explains why she disagrees. In her studies, this strategy increases vegetable consumption and decreases total calorie intake in both children and adults.

I agree: We think of it as smart health-wise cooking when people reduce salt or unhealthy fats, or replace refined grains with more nutritious whole grains, while still keeping it delicious. We don’t need to announce the changes; we just consider it improving a dish. To me, adding more vegetables is just another way of improving recipes, and it’s been a standard part of how I cook for many years.

• Fresh or frozen cauliflower or summer squash gets added to macaroni and cheese for studies using puréed vegetables at Penn State, and a recipe is included in Dr. Rolls’ Ultimate Volumetrics Diet.
• Puréed cauliflower, butternut squash, carrot and parsnips are all recommended additions to shepherd’s pie, tuna-noodle casserole or chicken-rice casserole, according to dietitian-TV chef Ellie Krieger, MS, RD. She also suggests pumpkin or fruit purée added to hot cereal or pancakes.
• Puréeing roasted red peppers or frozen peas for a dip or spread is another idea Ellie Krieger recommends. A spread featuring puréed green peas and roasted garlic, from AICR’s New American Plate Cookbook, is a favorite of guests at my home. (Sounded odd to me before I tried it, but yum, the garlic flavor makes it great.)
• Beans aren’t as low in calories as non-starchy vegetables like broccoli and spinach, but they do provide great thickness along with fiber and nutrition, and with fewer calories than when thickness comes from lots of cream or cheese. Especially when time is tight, open a can of beans, drain, rinse and quickly purée in a blender or food processor. White beans like cannellini, pinto beans or garbanzo beans work in a light sauce or soup; black beans work well in a dark-colored dish.

Put vegetables in the spotlight on their own
According to Dr. Rolls, including more vegetables in a main dish does not lead people to reduce consumption of vegetable side dishes, and side dishes do also help reduce the overall calorie density of a meal. Several factors influence how much we eat of vegetables served as side dishes.

• Offer vegetables in a soup or salad as a starter, when people are hungriest.
• Boost portions of vegetables served as a side dish. If you serve them from serving dishes, leave a big vegetable or salad serving bowl on the table, and remove the meat serving dish.
• Offer more than one vegetable side dish at each meal. If this seems overwhelming, think about super-simple options for at least one: perhaps raw carrots, or a simple salad. Or make some fruit, like apple slices, the second produce option, if that works better for you or your family.
• People eat larger portions of vegetables they think taste good. Especially for people who are not current veggie lovers, focus your flavor efforts on making vegetables super-delicious. For some people that’s as simple as a squirt of lemon juice or sprinkling of Parmesan cheese. For others, condiments that match their favorite ethnic foods may be the key. Get inspired by looking through websites like Cooking Light, or vegetable-friendly cookbooks, like Mollie Katzen’s The Vegetable Dishes I Can’t Live Without and Mary Lynn Farivari’s Healthy Palate.

Let’s talk: You don’t have to choose between these strategies. Have fun experimenting with different vegetables you can add to main dishes – either in full view or mixed in unseen – to reduce the calories per serving they provide. And play around with adding a variety of vegetables as side dishes, either as soup or salad starters, or as accompaniments to a main dish.

Please share some of your favorite ways of combining vegetables into mixed dishes. While you’re at it, share some ways you make vegetables side dishes flavorful without sacrificing nutrition.  Let’s all help each other use calorie density to eat better.

*Full disclosure: Barbara Rolls gave me a copy of the Ultimate Volumetrics Diet. However, this was presented as a gift long before this interview, and without any request or compensation for mentioning it or its recipes.

Resources
In addition to recipes, you can get detailed information about how to use calorie density to help you reach and maintain a healthy weight in Dr. Rolls’ latest book: Rolls, Barbara, with Mindy Hermann, RD. The Ultimate Volumetrics Diet. William Morrow, 2012.

For proof-positive of how delicious healthy eating can be, check AICR’s cookbook, which is built around meal proportions that promote good health and smart calorie density: The American Institute for Cancer Research. The New American Plate: Recipes for a  Healthy Weight and a Healthy Life. University of California Press, 2005.

For more ideas for mixed dishes that place the focus on vegetables, check the free American Institute for Cancer Research brochure, The New American Plate: One-Pot Meals.

Trouble making vegetables taste so good you and your family want to eat large portions as a side dish? Check this brochure from the AICR series, The New American Plate: Veggies.

Katzen, Mollie. The Vegetable Dishes I Can’t Live Without. Hyperion, 2007.

Farivari, Mary Lynn. Healthy Palate, Delicious and Simple Recipes to Enhance Meals with Fruits and Vegetables. Parsley Publishing. 2010.

References
Rolls, B., Roe, L., & Meengs, J. Portion size can be used strategically to increase vegetable consumption in adults. Amer J Clin Nutr, 2010. 91: 4 913-922.

Spill MK, Birch LL, Roe LS, Rolls BJ. Hiding vegetables to reduce energy density: an effective strategy to increase children’s vegetable intake and reduce energy intake. Am J Clin Nutr, 2011. 94(3):735-41.

Blatt AD, Roe LS, Rolls BJ. Hidden vegetables: an effective strategy to reduce energy intake and increase vegetable intake in adults. Am J Clin Nutr, 2011. 93(4):756-63.

Rolls B, Drewnowski A, & Ledikwe J. Changing the energy density of the diet as a strategy for weight management. J Amer Diet Assoc, 2005. 105(5 Suppl 1):S98-103.