If you are like most runners, you are busy juggling work, workouts, family, and life. You likely eat meals and snacks on the run, grabbing an energy bar here, a frozen meal there, and a protein shake to go. You can easily fuel yourself with highly processed foods that are ready to heat and/or ready to eat.
While you can choose a nutritionally well-balanced sports diet when eating on the run, you might want to pay attention to the amount of ultra-processed foods that sneak into your meals and snacks. They have a food matrix far different from natural foods, and they might have an impact on your weight and health.
What are ultra-processed foods?
Cooked eggs, canned beans, and dried raisins are all considered processed foods. Technically speaking, a processed food is one that has been altered from its original form. The foods have been cooked, dried, or canned in a way that’s safe for your health.
Ultra-processed foods include fast foods, sugary drinks, chips, candies, sweetened cereals, etc. They span the spectrum from minimally processed foods that are prepared to make them edible (bran flakes) to industrial formulations with five or more ingredients (Cap’n Crunch). Ultra-processed foods commonly have added flavors, sugars, fats, preservatives and ingredients that you are unlikely to have stocked in your pantry, like sodium benzoate. These foods are designed to be convenient, ready to eat, palatable, affordable and welcomed as replacements for freshly prepared meals and snacks.
More than half the calories consumed in the US come from ultra-processed foods (think packaged soups, instant noodles, frozen meals, hot dogs, cake mixes.) The foods tend to be high in calories, salt, and fat, and low in fiber. Ultra-processed foods can be marketed as natural, healthy and organic. (Those words don’t refer to the process of how the food was made.) Yes, your favorite all-natural, organic energy bar likely counts as an ultra-processed food.
A diet rich in ultra-processed foods has been associated with high blood pressure, heart disease, Type 2 diabetes, and stroke. While these foods might not cause those health problems, people with the health issues are more likely to consume a fair amount of ultra-processed foods. We need more research to determine if these easy-to-overeat foods are the problem (“I can’t eat just one…”), or if their high caloric density makes them easier to over-consume.
Ultra-processed foods and your waistline.
Speaking at the Academy of Nutrition and Dietetics’ (AND) 2019 Food and Nutrition Conference and Expo (FNCE), Kevin Hall PhD of the National Institutes of Health spoke about the ease of weight gain among people who eat a plethora of ultra-processed foods. He conducted a study in which 20 healthy adults (10 men, 10 women) ate as much or as little as they wanted for 14 days from a buffet of minimally-processed or ultra-processed foods (1). The buffets were matched for calories, sugar, fiber, carbohydrate, protein, fat and salt. The subjects rated both diets as being equally palatable. Yet, when the subjects ate from the ultra-processed buffet, they consumed about 500 calories above their baseline intake and they gained about 2 pounds in two weeks. (Some of that weight gain can be attributed to water-weight, given the ultra-processed foods they chose were higher in sodium than their standard diet.)
When the subjects ate the unprocessed diet, they chose their typical caloric intake, yet they lost about 2 pounds in two weeks. How could that be? Some weight loss was related to water-weight loss, but some might have been related to a higher amount of calories needed to digest the whole foods. (This is called the Thermic Effect of Food—the increase in the body’s metabolic rate related to the consumption, digestion, metabolism and storage of food.) Foods in their natural state take more energy to be digested and metabolized than highly processed foods. For example, a grilled cheese sandwich made with whole wheat bread and cheddar cheese uses about 20% of the ingested calories to digest and metabolize the nutrients. In contrast, the same sandwich made with white bread and processed American cheese uses only 11% of ingested calories (2)
Ultra-processed foods tend to be high in simple-to-digest sugar, with a low thermic effect. They also tend to be low in fiber. Fiber-calories are not readily accessible to the body. Almonds, for example, reportedly offer 170 calories per ounce (23 almonds), as written on the food label. The reality is, your body can access only 130 of those calories (3). Fiber-rich plants foods can be better for your waistline (and your overall health).
Processing changes the food structure (matrix), and this impacts satiety, the feeling of fullness that persists after eating. The more a food is processed, the lower it’s satiety, likely related to the higher its glycemic response (rise in blood glucose). Simply put, devouring 500 calories of ten (ultra-processed) Oreos is far easier than chewing through 500 calories of almonds (~70 almonds) and is far less satiating.
The bottom line
At this time, we have no data to confirm that ultra-processed foods cause weight gain, but they are certainly associated with weight gain. Dr. Hall is planning another study to look at the impact of energy-density on calorie intake. Til then, common sense tells us for weight management, your best bet is to snack on whole grains, fresh and dried fruits, nuts and other minimally processed foods. Limiting ultra-processed foods may be an effective weight-management strategy.
References:
1) Hall, K et al. Ultra-processed diets cause excess calories intake and weight gain: An inpatient randomized control trial of ad libitum food intake. Cell Metabolism 2019; 30:67-77.
2) Barr, S. and J. Wright. Postprandial energy expenditure in whole-food and processed-food meals: implication for daily energy expenditure. Food & Nutrition Research 2010; 54: 5144-5153.
3) Novotny J. et al, Discrepancy between the Atwater factor predicted and empirically measured energy values of almonds in human diet. Amer J Clin Nutr 2012 96(2):296-301.
Sports Nutritionist Nancy Clark, MS, RD counsels both casual and competitive athletes at her office in Newton, MA (617-795-1875). The new 6th edition of her best selling Sports Nutrition Guidebook addresses today’s questions and concerns about what to eat. For more information, visit www.NancyClarkRD.com. For her online workshop, see NutritionSportsExerciseCEUs.com.