When it comes to losing weight, most people understand that it is necessary to burn more calories than what you consume. However, they are reluctant to place restrictions on calorie intake out of fear that they will be left feeling hungry and deprived (which as stated in a previous post, can sabotage weight loss efforts). What most people don’t realize is that it’s possible to reduce your calorie intake while maintaining or even increasing the amount of food you consume. And while this approach to weight loss may sound too good to be true, it’s principles are supported by research and form the foundation of the “Volumetric Eating Plan”.
The volumetric eating pattern was developed by nutrition researcher, Barbara Rolls (1), and contends that weight loss can be achieved and maintained by focusing on the energy density of food, rather than specific macronutrients and ratios. Energy density refers to the number of calories (which in scientific terms, is a measure of energy) a food has per a standard weight unit, such as 1 gram.
The energy density of the human diet is as follows:
| calories/gram | |
| Water | 0 |
| Fibre | 2 |
| Carbohydrates | 4 |
| Protein | 4 |
| Alcohol | 7 |
| Fat | 9 |
By far, water has the greatest influence on energy density as it increases the weight (or volume) of food, without adding calories. However, water only influences satiety or fullness when it’s found naturally in a food like fruit or vegetables or is added to a food like soup; consuming beverages doesn’t have much of an impact on satiety since liquids empty from the stomach quickly. In contrast, fat can significantly increase the calorie density of our food since a small amount adds a lot of calories, without benefiting short-term satiety.
How to Use Volumetrics
Increase Low-Energy Dense Foods
Start by focusing on the entrée at each meal. Are the ingredients you are using high or low in energy? Are you adding vegetables or other low-calorie ingredients? Can you substitute sauces, oils, and butters for broth, herbs, and spices? Use the following chart to help plan meals, replacing energy dense ingredients with those that are lower in calories:
| Energy Density | Calories per Gram | How to Eat | Examples |
| Very low | 0.0 – 0.6 | Free foods – anytime | Fruits, vegetables, broth-based soups, unsweetened plant milks |
| Low | 0.6 – 1.5 | Eat reasonable portions – be mindful of servings | Cooked grains, lean meats, beans and legumes, low-fat mixed dishes (chili, pasta) |
| Moderate | 1.5 – 4.0 | Manage portions by measuring | Meat, cheese, bread, snack foods (crackers, popcorn, pretzels), mixed dishes (pizza, macaroni and cheese, burgers), nuts |
| High | 4.0 – 9.0 | Manage portions by measuring and reducing how often these foods are consumed | Crackers, chips, cookies, butter, oil |
Adapted from The Ultimate Volumetric Diet: Smart, Simple, Science-Based Strategies for Losing Weight and Keeping it Off by Barbara Rolls, PhD with Mindy Hermann, RD.
In addition to swapping high-energy dense for low-energy dense ingredients in your entrée, you may also want to start your meals with a broth-based soup, large leafy green salad, or some fresh fruit. Not only does this add nutrients to your meal, it increases satiety by filling up your stomach with low-energy dense foods, causing you to eat a smaller portion of your main meal.
Be Mindful of Added Oils and Butters
Olive oil is an ingredient that seems to be added to most recipes, regardless of whether it is needed for the cooking process or not. To put the energy density of oil into perspective, keep in mind that 1 tbsp of olive oil is the calorie equivalent of ~15 cups of kale, 2 cups of raw carrots, ½ cup cooked quinoa, or 1 ½ small apples. And which do you think is going to have a more profound effect on satiety, 15 cups of kale or 1 tbsp of olive oil?
This isn’t to say that fat should be feared or avoided, but it’s better to get your fat from whole food sources, such as nuts, seeds, avocado, hemp, flax, etc. When using oil or butter, try to add the smallest amount possible and use cooking substitutes like broth or water often.
Include Protein and Fibre with Each Meal
It is well-accepted that protein is a satiety-inducing nutrient. However, in the pursuit to of adding protein to literally everything, fibre often gets left behind. Studies show that high-fibre diets are associated with lower body weights and contribute to fullness by increasing chewing time, promoting stomach expansion, and delaying gastric emptying (1). The best (and in my opinion, tastiest) source of fibre are beans and lentils. Other excellent sources include berries, kiwis, pears, raw vegetables, whole, unprocessed grains, wheat bran, oat bran, flax, chia, and hemp seed.
Be Mindful of Added Sugars
Many people attempting to lose weight are wary of fruit due to the presence of naturally occurring sugars. However, it’s not the sugar in fruit that we need to be concerned with but rather the large amounts of concentrated sugar that are added to processed and packaged foods. Remember, because fruit has a high water content and is a source of fibre, it has a favourable impact on our satiety. In contrast, packaged foods tend to have very little water and fibre and the sugar that is added can greatly increase the energy density of the item.
Water is All You Need
As mentioned, beverages have little impact on satiety since they aren’t chewed and leave the stomach quickly. For this reason, it’s important to take stock of your beverage choices to ensure they aren’t a hidden source of calories. Water, black coffee, tea, unsweetened plant milks, and carbonated water are great low-calorie beverage choices to include in your daily diet. Juice, and to a lesser extent, cow’s milk, contain a concentrated source of sugar and should be limited. Alcohol is not only energy dense at 7 calories per gram, it also lowers inhibitions and can stimulate your appetite, making it difficult to say “no” to that second helping of supper or third handful of chips.
References
- Smethers AD, Rolls BJ. Dietary management of obesity: Cornerstones of healthy eating patters. Med Clin N Am 2018;102(1):107-124. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/29156179
