A protein bar for breakfast, a lavender-vanilla latte with raspberry cold foam to get through a 9 a.m. class. We call it fuel, but what if our brain interprets it as stress instead of sustenance? As it turns out, most of the foods we consume are ultra-processed, which may contribute to metabolic dysfunction.
Dr. Robert Lustig, emeritus professor at UC San Francisco and expert in nutrition and metabolism, recently gave a lecture with the Library Speakers Consortium about ultra-processed foods (UPFs) and their metabolic health impact. He points to sugars, a subset of carbohydrates, as the biggest nutrient of concern associated with UPFs and poor metabolic health outcomes.
So what constitutes UPFs? In 2009, Dr. Carlos Monteiro at the University of São Paulo developed the NOVA system to categorize all food into four groups ranging from unprocessed to extensively processed. UPFs land in the fourth group, defined as food products made up of many ingredients that result from industrial processes.
Dr. Lustig describes these foods as “nutritionally empty,” lacking fiber, vitamins and minerals. A primary reason for this is refined flour being a main ingredient of UPFs. Flour is made from grain, which consists of three parts: the endosperm (starch and protein), the bran (fiber) and the germ (oil and vitamins). When UPFs replace whole foods in our diets, they reduce our intake of protective nutrients. Whole foods refer to items in their most natural states with minimal processing.
Beyond refined flour, UPFs also contain artificial ingredients, preservatives and sugars. These foods are low in nutrients and high in calories, sugar, sodium and unhealthy fats, including saturated and trans fats.
These fats raise LDL (bad) cholesterol levels and can contribute to increased inflammation. The high sugar content of UPFs can increase the risk of obesity, insulin resistance, type 2 diabetes and other metabolic diseases. UPFs trigger rapid spikes in blood sugar and insulin, which promote fat storage and increase the risk of metabolic diseases.
Overconsumption of UPFs is not only a result of consumer choice, but is a larger, multifaceted issue tied to food industry practices and food access.
According to Dr. Lustig, UPFs make up 57 percent of the United States’ population’s diet, and 73 percent of the food supply in the United States. Particularly, limited access to non-UPFs is exacerbated when considering cost and affordability of these foods relative to UPFs. Fresher ingredients and foods are much more expensive due to short shelf lives and additional production-related costs for storage and transportation. In contrast, Dr. Lustig mentions that UPFs are more often subsidized, as their base ingredients include subsidized crops like corn, wheat, soy and sugar. For individuals who depend on food assistance programs, these UPFs may be the only option.
A 2019 study that compared UPFs to whole foods found that UPFs have a much lower cost per calorie ($0.55 vs. $1.45 per 100 kcal) and are more energy-dense (2.2 vs. 1.1 kcal per g). Over 12 years, non-UPFs increased in price more than UPFs, making UPFs a more affordable and convenient option. This means that UPFs can provide more energy for less money as compared to whole foods.
However, UPFs have lower nutrient density — the valuable nutrients in a food relative to its calorie content — compared to whole foods, resulting in the intake of far fewer micronutrients relative to total calories. UPFs earned a nutrient density score of 21.2 versus a nutrient density score of 108.5 for whole foods.
A literature review from the World Nutrition Journal, focusing on evaluating the factors contributing to the appeal of UPFs, listed several findings about UPF consumption in relation to socio-demographic, cultural and economic factors.
The authors found a negative relationship between UPF consumption and age, but a positive relationship between preference for sweeter and saltier tastes and age. Research from the Global North suggests that higher consumption of UPFs is more prevalent among populations with lower socioeconomic status. Overall, UPF consumption worldwide is increasing, and there is a growing vulnerability to UPFs and their adverse health consequences among poorer populations.
Reducing our consumption of UPFs is not about restricting our diet, but about replacing foods that work against the body with foods that support it.
Whole foods such as vegetables, fruits, nuts, legumes, whole grains and minimally processed proteins function differently in the body than UPFs do. Whole foods support healthy heart function, improve metabolic and gut health, enhance mental health and cognition and reduce addictive eating patterns. Whole foods contain complex carbohydrates and fiber, which means they are digested more slowly, stabilizing blood sugar and insulin levels in turn and reducing fat storage and the risk of metabolic disease. Many of these whole foods are rich in vital nutrients, including potassium, healthy fats and antioxidants, which help lower blood pressure, improve cholesterol levels and reduce inflammation, thereby protecting against heart disease and stroke.
Some realistic recommendations for reducing UPFs and increasing whole foods include:
- Add before you subtract
Before looking at what to cut, try adding.
- A handful of nuts
- 1-2 servings of fruits or vegetables a day
- Some whole grains, such as barley and brown rice
- Add legumes to your meal
- Swap! Don’t eliminate everything at once
Make replacements to your diet.
- Whole-grain bread instead of white bread
- Oats instead of sugary cereal
- Choose foods with fiber
High-fiber fruits and vegetables:
- Apples
- Berries
- Broccoli, brussels sprouts, cabbage and corn
- Dried fruits
- Green leafy vegetables
- Peas, potatoes with skins and sweet potatoes
Other fiber-rich foods:
- Plain popcorn (not microwave bags)
- Nuts and seeds
- Whole-grain bread and pasta
- Buy frozen, not just fresh
Frozen fruit and vegetables are equally nutritious to fresh options and are often cheaper.
These aren’t rules or restrictions, they’re just a few small ways to reduce UPFs in your daily life. The goal is not to create guilt, but to nourish the body with more whole foods whenever possible. Restrictive dieting can be physically and emotionally harmful, but intentional dieting is key in supporting metabolic and cognitive health!
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