Excessive intake of ultra-processed foods may cause obesity, cancer, and cognitive decline! What are ultra-processed foods?

Ultra-processed foods (UPF) are foods that have gone through multiple steps and cannot be made in a home kitchen. They also contain a lot of additives to enhance flavor, texture and shelf life. Studies have shown that the average American gets nearly 60% of their calories from ultra-processed foods. According to a study by Professor Li Meixuan of the National Defense Medical Center in Taiwan, the increase in UPF consumption among high school students between 1993 and 2011 caused a decline in the quality of their diet and also increased the obesity rate. In addition, UPF has been proven to be positively correlated with cancer incidence and mortality, so we must be cautious.

What are ultra-processed foods? NOVA food categories at a glance

What are ultra-processed foods? Dr. Zheng Naiyuan, director of the Lian'an Preventive Medicine Institute, said that according to the NOVA food classification system created by the University of São Paulo in Brazil, processed foods are divided into four categories, of which the fourth category is ultra-processed food, which should be avoided as much as possible. A healthy diet should be based on the first and second categories, while the third category should be consumed in reduced amounts.

Category 1: Unprocessed or minimally processed foods, i.e., raw foods such as rice, fresh fish, fruit, fresh milk, dried beans, etc.

Category 2: Processed cooking ingredients, such as oil, sugar, salt and flour.

Category 3: Ready-to-eat foods, that is, processed foods flavored with condiments (Category 1 + Category 2), such as canned fish, ham, kimchi, dried meat, seasoned nuts, and freshly made bread; common local Taiwanese dishes, such as dumplings, stinky tofu, pig blood, oyster omelette, fish floss, meat floss, and pan-fried buns.

Category 4: This category of food is highly processed and often contains artificial flavors, pigments, stabilizers and other additives to improve the taste and extend the shelf life, such as frozen pizza, biscuits, fast food, etc.

NOVA food classification (Photo provided by Lian'an Preventive Medicine Institute)

While moderate processing can help preserve nutrients and extend shelf life, the process by which ultra-processed foods are made often deviates from natural foods, which is where health risks come from. UPF may also cause addiction problems due to its convenience and smooth taste. A US study showed that 14% of adults and 12% of children are addicted to UPF. This addictive nature makes it difficult to control intake and affects overall health.

Beware of the 4 major health effects of consuming too much ultra-processed food

Dr. Zheng Naiyuan said that many studies have shown that frequent consumption of ultra-processed foods may have serious effects on health, mainly in the following four aspects:

1. Metabolic diseases such as obesity and hypertension

Ultra-processed foods often contain large amounts of starch, sugar, and saturated fat, and have an extremely high calorie density. The calories in the same weight are much higher than those in minimally processed or unprocessed foods. A multinational European study analyzed daily diets using the NOVA food classification and found that people consumed 71.5% of the weight of NOVA Category 1 foods and 35.9% of the calories, while Category 4 ultra-processed foods accounted for only 13.7% of the weight but 32.0% of the calories. Therefore, regular consumption of ultra-processed foods may lead to metabolic diseases such as obesity, type 2 diabetes and hypertension.

2. Imbalance of intestinal flora causes leaky gut

Ultra-processed foods lack dietary fiber and contain large amounts of chemical additives, which may change the composition of the intestinal microbiota, cause intestinal health problems, and trigger chronic inflammation. Adverse changes in intestinal flora can affect overall immune and digestive functions, and may even cause leaky gut syndrome, making it easier for harmful substances to enter the blood and lead to more health problems.

3. Accelerated cognitive decline

Research shows that for consumers under 60 years old, if UPF consumption exceeds 19.9%, overall cognitive decline accelerates by 28% and executive function decline accelerates by 25%. Consumers over 60 years old have no particular impact on the UPF consumption ratio, but this also reminds us of the necessity of early prevention and reducing the intake of ultra-processed foods. In addition, frequent intake of excessive amounts of sugar and ultra-processed foods such as sweet baked goods can also have a negative impact on young children's cognitive functions, especially language comprehension ability.

4. Increased cancer incidence

UPF usually contains empty calories, which means lack of nutrients such as vitamins, minerals and protein. The main source of calories is added sugar and unhealthy fat, and the nutritional value is low. UPF is low in dietary fiber, high in carbohydrates, high in salt, high in saturated fat, and may contain harmful additives and pollutants, so it may be carcinogenic.

Beware of the four major health effects of consuming too much ultra-processed food (Photo courtesy of Lian'an Preventive Medicine Institute)

In addition, UPF packaging may contain bisphenol A (BPA), phthalates, per- and polyfluoroalkyl substances (PFAS), and phenols. Phthalates are commonly used in plasticizers and can disrupt endocrine system; PFAS are used in waterproof and oil-proof coatings and may cause cancer; phenols can disrupt the hormone system. These chemicals may be released when they come into contact with food and absorbed by the body, thereby increasing the risk of cancer.

4 tips to avoid excessive intake of ultra-processed foods

With the popularity of ultra-processed foods in daily life, more and more studies have shown the harm of UPF to the human body. Therefore, many countries have taken relevant actions to reduce the intake of UPF. For example, Mexico introduced a sugary beverage tax in 2014, which has effectively reduced sales of sugary drinks by approximately 7.6%. Other countries such as the United Kingdom and South Africa have also reduced consumption of sugary drinks through similar tax policies, further confirming the effectiveness of policy interventions. Brazil, Peru, Uruguay, Ecuador and Canada have also adopted food guidelines to encourage people to avoid ultra-processed foods.

Taiwan can learn from the experience of other countries to reduce excessive intake of ultra-processed foods, and rely on policy promotion and supervision from relevant units. At the same time, Chinese people should also actively understand the nutritional content of the food we consume, improve health awareness, and reduce dependence on ultra-processed foods. We can start with the following 4 points:

4 points to avoid excessive intake of ultra-processed foods (Photo courtesy of Lian'an Preventive Medicine Institute)

1. Choose original foods or minimally processed foods:

Prioritize fresh fruits, vegetables, whole grains, and natural meats. These foods are rich in fiber, vitamins and minerals that help maintain good health.

2. Avoid ultra-processed foods:

Avoid ready-to-eat, microwave-heated, preheated, brightly colored, strongly scented, or heavily flavored foods, or foods that can be stored for a long time. Although these foods are convenient and delicious, their high sugar, salt and fat content can increase health risks.

3. Pay attention to food ingredient lists and nutrition labels:

When purchasing processed foods, read food labels carefully and avoid choosing products that contain large amounts of additives, such as artificial flavors, colors, flavor enhancers, thickeners, etc. It is healthier to choose foods with simple ingredients and few additives.

4. Develop good eating and cooking habits:

Control the quality of ingredients and the use of seasonings, reduce eating out as much as possible, and avoid overly complicated cooking methods.

By adopting the above strategies, we can effectively reduce the intake of ultra-processed foods, gradually establish healthy eating habits, and promote a healthy culture in society as a whole.