How Ultra-Processed Diets Cause Obesity
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It is becoming increasingly known that a diet high in ultra-processed foods is associated with negative health outcomes such as cognitive decline, diabetes, cardiovascular disease and obesity. Ultra-processed foods are typically low in beneficial macro and micronutrients and fiber and high in chemical additives and excess sugar.
“…we are a nation that is overfed and undernourished.”
With around 60 percent of the average American’s diet made up of ultra-processed foods, it is no wonder we are a nation that is overfed and undernourished. Yet many claim that food quality is not nearly as important as quantity when it comes to preventing obesity, and that calories should be the main focus of our diets.
However, emerging research suggests that ultra-processed foods may in fact increase a person’s food cravings, energy intake and contribute to weight gain.
In a 2019 study, researchers investigated whether an ultra-processed diet would impact the energy intake of 20 “weight-stable” adults. Participants were randomly assigned to either an ultra-processed or unprocessed diet for 2 weeks followed by the alternate diet for 2 additional weeks. Participants could eat as much or as little as they wanted at each meal, but meals consisted of equal “calories, energy density, macronutrients, sugar, sodium, and fiber.”
“…energy intake was higher while consuming ultra-processed foods and participants gained weight while consuming the ultra-processed diet. “
The researchers found that energy intake was higher while consuming ultra-processed foods, and participants gained weight while consuming the ultra-processed diet. When consuming the unprocessed diet, participants ate fewer calories, fewer refined carbohydrates and lost weight. These findings suggest that consuming an unprocessed diet is helpful for preventing, and possibly treating, obesity. Furthermore, since energy density and nutrients were kept the same across the diets, it is likely that differences would have been even more apparent if meals had better reflected the typical nutritional discrepancies of ultra-processed and unprocessed foods.
“…these meals are less satiating and do not provide the body with adequate nutrients.”
While consuming excess calories can promote weight gain regardless of food quality, it is important to note the impact of ultra-processed versus unprocessed food components on appetite and energy intake. It is much easier to overeat when a meal is lacking in necessary macro and micronutrients such as protein, healthy fats and fiber as these meals are less satiating and do not provide the body with adequate nutrients.
As discussed in previous posts, ultra-processed foods are generally engineered to be extremely palatable and addicting with the use of artificial flavors, sugar or sweeteners, unhealthy fats and additives such as salt. It is possible that these foods “disrupt gut-brain signaling and may influence food reinforcement and overall intake via mechanisms distinct from the palatability or energy density of the food.”
“Blood sugar dysregulation can lead to increased cravings, especially for more high sugary foods.”
Additionally, these foods are often higher in sugar and lower in fiber, contributing to dysregulated blood sugar when consumed daily or over a long period of time. Blood sugar dysregulation associated with postprandial insulin spikes can lead to increased cravings, especially for more high sugar foods. In the long run, heightened blood sugar levels can also lead to insulin resistance wherein the body cannot effectively use glucose and the excess is stored as body fat.
“A diet rich in nutrient dense, minimally processed foods […] is likely to promote positive health outcomes…”
It is not possible to make any causal claims from this study due to the small sample size and other extraneous variables, however mounting evidence does support a causal link between ultra-processed diet and negative health outcomes.
It is obvious that the consumption of processed foods is part of most modern diets. Such processing includes cooking, baking, fermentation and freezing. However, it is now well known that minimizing ultra-processed foods in general is beneficial for overall health. A diet rich in nutrient dense, minimally processed foods such as fruits, vegetables and protein, similar to that of a Mediterranean-style diet, is likely to promote positive health outcomes and prevent the onset of obesity and other chronic non-infectious diseases. An active lifestyle, adequate sleep and stress management are also important factors that can aid in the prevention and management of these diseases.