Throughout history, humans have needed to process food to increase its shelf life, improve its taste and quality. But these processing practices have become increasingly complex due to the high demands for novel, hyper-palatable, and convenient products, and industry has taken it upon itself to provide them, selling them with highly aggressive marketing. Because of this and other factors such as sedentary lifestyle, diseases like obesity, type 2 diabetes, or many types of cancers have been increasing exponentially.
Thanks to the NOVA system by Carlos Monteira, we are able to detect nowadays the degree of processing of our products:
- NOVA 1: Unprocessed food or minimally processed food, like... fresh vegetables, whole grains, meat, fish...
- NOVA 2: Culinary ingredients that you must have in your kitchen like sugar, honey, flours, salt, pepper... That helps increase flavor and the texture of the recipes.
- NOVA 3: Processed foods. These are usually a mix of NOVA 1 and NOVA 2 ingredients. It is common for these products to contain few ingredients, some examples are canned fish and vegetables or yogurts.
- NOVA 4:Ultra-processed products. Products with a long list of ingredients and additives such as flavors, colorants, flavor enhancers... To add more pleasure senses to the final product.
In the recent webinar, Joint Programming Initiative - A Healthy Diet for a Healthy Life (JPI HDHL) broadcast on June 15, Dr. Kevin Hall presented his study published in 2019 by the journal Cell metabolism: Ultra Processed Diets Cause Excess Calories. Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake.
Kevin Hall and his colleagues wondered whether a diet rich in ultra-processed (UP) products compared to a whole food diet with almost identical nutrient values (calories, sugar, fiber, sodium, fat...) could have an impact on our eating behavior.
In this study they selected 10 men and 10 women of stable weight and had them reside for 28 days at the NIH Clinical Center to assess their eating behaviors. Subjects were randomly assigned to either the UP or unprocessed diet for 2 weeks followed immediately by the alternate diet for the final 2 weeks. The two diets had almost the same nutrient profile, but the UP rich diet had 80% of the food provided for NOVA 4 group, and the unprocessed diet 0% food provided for NOVA 4 group.
Participants could eat as they pleased, with no restrictions, simply limiting themselves to the meal pattern served to them by the team of nutritionists according to their UP-rich or whole food-rich diet. At the end of each meal, the team's main objective was to measure the leftovers to assess the individuals' intake.
The results show how the participants ate 500 kcal/day more during the rich in the UP diet and at the same time their body weight values increased at that period of time. That is, the UP makes us eat more and as a consequence we gain more weight.
But some questions arose in these findings, since the results obtained are an average of the participants. Some participants did not really show differences in the rich UP diet and the unprocessed diet and others were more sensitive to eating more in the rich UP. How is it possible that some people are more likely to overeat when consuming UP?
The macronutrients that increased the most in the UP-rich diet were fats and carbohydrates. Blood glucose levels were also assessed and there were no differences between the two diets.
The subjective sensations of the individuals were evaluated by questionnaires to detect some other relationships on the results obtained, but there were no differences between diets on the levels of pleasure, familiarity or hunger/satiety.
In conclusion, the final data of the study suggest that eliminating UP foods from the diet decreases energy intake and results in weight loss, whereas a diet with a large proportion of UP food increases energy intake and leads to weight gain.
To further investigate the causes of this association, Dr. Hall is currently investigating new hypotheses that have arisen during the course of the study. He is currently studying how hyperpalatibity linked to UP affects eating behavior in order to find new strategies to prevent this stage of overeating in a UP rich diet. But finally the main conclusion is the same, the best way to prevent illness associated with UP is to reduce their consumption.
Article written by Laura Guinovart Martín, certified Dietitian and Nutritionist; Specialized in TCA, Obesity and Food Development and Design; Nº Col:CAT002123
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