“Eating smart, not eating less, may be the key to losing weight.”
Those are the words that opened an article in Science Daily on June 8, 2007. That day, the publication was featuring a new study that showed eating a diet low in something called “calorie density” helped participants lose weight, without the restrictions seen in other diets.
But what is calorie density, and how might it work for you?
What is Calorie Density?
For decades now, health experts have told us that the key to losing weight is to eat less and exercise more. The idea was that taking in less food while burning more through daily activity would result in weight loss, but this traditional advice has failed miserably when it comes to actually helping people stay healthy.
Faced with our current obesity epidemic, scientists went back to the drawing board to figure out just how to get around our modern-day dilemma of the expanding waistline. The idea of depriving ourselves and ignoring our hunger cues is just not working.
New studies started coming to light, and these studies suggested something new—it’s not about how much food you eat overall, but what kinds of foods you eat. After all, some foods pack more energy into every bite than others—what’s called “calorie density” or “energy density.”
How many calories are in one ounce of your favorite foods? That’s what you need to find out, because according to new science, this could be the key to staying satisfied and lean.
Studies Show It Works
Penn State researchers studied 71 obese women aged 22 to 60. They split them into two groups, and gave one group a reduced-fat diet, and the other a reduced-fat diet also high in water-rich foods, such as juicy fruits and soups. All women were taught how to choose foods low in calorie density, but they were not restricted in how many calories they could consume each day.
After one year, the results showed:
- Women in both groups showed significant weight loss.
- All women showed a decrease in the calorie density of their diets.
- The women who added water-rich foods lost more weight during the first six months than those who only reduced fat in their diets—19.6 pounds compared to 14.7 pounds.
- Subjects in both groups maintained weight loss during the second six months of the study.
- Women who included more water-rich foods ate 25 percent more food by weight and felt less hungry than those who followed the reduced-fat diet, yet they still lost more weight.
This study was huge in the dieting market, as it showed that people could actually eat more food pound-for-pound, yet still lose weight.
“By eating more fruits and vegetables,” said Dr. Julia A. Ello-Martin, lead author of the study, “they were able to eat more food, and this probably helped them to stick to their diet and lose more weight.”
“Choosing foods that are low in calorie density helps to control hunger,” said Dr. Barbara J. Rolls, who directed the study and who holds the Helen A. Guthrie Chair of Nutritional Sciences at Penn State, “and is a healthy strategy for losing weight over the long term.”
Second Study Shows Similar Results
Only four years later, another study came out on calorie density, showing similar results. Five nutrition and public health experts at Harvard University analyzed data from over 120,000 men and women who were healthy and not obese at the start of the study. These people were part of the Nurses’ Health Study, Nurses’ Health Study II, and the Health Professionals Follow-Up Study, and were followed for 12 to 20 years.
The results showed:
- The average participant gained 3.35 pounds every four years, for a total weight gain of 16.8 pounds in 20 years.
- Those who exercised less over the course of the study gained weight, while those who increased their activity didn’t.
- Those with the greatest increased activity gained 1.76 pounds fewer than the rest.
- The kinds of foods people ate had a larger effect overall than changes in physical activity.
- Foods that contributed to the greatest weight gain were calorie dense, and included things like French fries, potato chips, sugar-sweetened drinks, red meats, processed meats, other forms of potatoes, sweets and desserts, refined grains, other fried foods, fruit juices, and butter.
- Foods that resulted in weight loss or no gain when consumed in greater amounts included fruits, vegetables, and whole grains.
- Compared with those who gained the most weight, participants who lost weight consumed 3.1 more servings of vegetables each day.
- Weight loss was greatest among people who ate more yogurt and nuts.
How to Apply Caloric Density to Your Life
If you can truly eat more of some foods and still lose weight, how can you apply this idea to your own life? First, it helps to know the basics of the idea of calorie density. Think of the composition of a particular food. Water lowers the energy density, because it contributes weight but not calories. Fiber also has a relatively low energy density.
On the other side of the coin, fat is the most energy dense component of food, providing twice as many calories per gram as carbohydrates or protein. In general, foods with a lower calorie density (fruits, vegetables, broth-based soups) tend to have a high water content, lots of fiber, and little fat.
Here are seven tips to help you control hunger pangs and cravings by working with the principle of calorie density:
- Choose foods low in calorie density: These include foods that are high in water content but low in fat. Think watermelon, grapes, clear soups, and lean protein rather than donuts, potato chips, and pretzels.
- Add in low-density foods: If you’re fixing a casserole, add in more water-rich vegetables like spinach, zucchini, celery, and carrots, to lower the overall calorie density. In general, incorporate a large portion of fruits and vegetables into all meals.
- Do some figuring: To determine the calorie density of any particular food, look at the Nutrition Facts on the back. Divide the calories per serving by the weight of a serving. For instance, a serving of pudding may have 100 calories per serving, with the serving measuring 110 grams. Divide 100 by 110, and you get a calorie density of 0.9 calories per gram. This makes the pudding a better option than a chocolate bar, for instance, that would have a calorie density of 5.1 calories per gram. (230 calories divided by 45 grams.) Find a general chart for low-to-high energy measurements below.
- Keep high-density portion sizes small: Some foods—like nuts and raisins, for instance—are high caloric density, but still important for a healthy diet. Include these as you wish; simply pay attention to portion sizes, and fill out your plate with low-density options.
- Dress down your desserts: If you have a sweet tooth, you can still enjoy that ice cream—just cut your serving in half and add in some fresh fruit with it. Try a half-cup of reduced-fat ice cream with a half-cup of strawberries, for example.
- Enjoy appetizers: Eating a low-density appetizer before a meal can help you eat less overall. Try a broth-based soup or green salad at the start of your meal.
- Make low-density foods more available: If you’re struggling with your weight loss goals, stock up on low-density foods in your home and office. Have cut-up fruits and vegetables, light yogurt, popcorn, and the raw materials for green smoothies nearby.
Calorie Density Measurements
- 0.0 – 0.7 Very low
- 0.8 – 1.5 Low to moderate
- 1.6 – 3.0 Moderate to High
- 3.1 and Up Very High
Have you lost weight using the principle of calorie density? Please share your story.
* * *
Penn State (2007, June 8). Calorie Density Key To Losing Weight. ScienceDaily. Retrieved August 20, 2013, from http://www.sciencedaily.com /releases/2007/06/070608093819.htm.
Jane E. Brody, “Still Counting Calories? Your Weight-Loss Plan May Be Outdated,” NYTimes, July 18, 2011, http://www.nytimes.com/2011/07/19/health/19brody.html?pagewanted=all&_r=0.
Dariush Mozaffarian, et al., “Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men,” New England Journal of Medicine, June 29, 2011, http://www.nejm.org/doi/full/10.1056/NEJMoa1014296?query=TOC#t=articleTop.
“Low-Energy-Dense Foods and Weight Management: Cutting Calories While Controlling Hunger,” CDC, http://www.cdc.gov/nccdphp/dnpa/nutrition/pdf/r2p_energy_density.pdf.