A recent study published in the journal Obesity suggests that highly processed foods may be driving the obesity epidemic by increasing “protein hunger” and causing people to overeat. In this article, we’ll explore what processed foods are, how processed foods cause weight gain. Read on to learn more.
What are Processed Foods?
Technically, almost everything you consume is processed. Any food that goes through a manufacturing plant before it lands in your grocery cart is processed. This includes a large number of completely harmless foods: pre-washed spinach, pre-cut broccoli, frozen strawberries. These are all processed foods.
When nutritionists warn that processed foods cause weight gain, what they are really talking about are highly processed foods. These are foods that contain industrial ingredients, including:
- High-fructose corn syrup
- Hydrogenated oils
- Flavoring agents
- Fruit juice concentrate
In fact, the ingredient list is a great resource for determining how your food is processed. If the label lists items that you would never use to cook from scratch, the product is far from its natural state. The question is: Does it matter?
Yes, it matters. Natural, whole foods are essential to a healthy diet and good weight management.
The purpose of processing is to make food more convenient, cheaper, longer lasting and tastier. But there is no doubt that these benefits often come at the cost of weight gain or lack of health, such as lack of energy, poor sleep or digestion, and other chronic diseases. Here’s why.
How Processed Foods Cause Weight Gain?
The Ingredients in Processed Food that Make You Fat
In general, ultra-processed foods tend to contain high types of calories, salt, fat and sugar compared to whole foods. In fact, processed foods are responsible for nearly 90% of the sugar added to the regular diet. For example, fructose or simple carbohydrates react very differently in the body than refined sugars. Trans fats are more unhealthy than natural fats. Salt used for preservation does not have the same beneficial properties as himalayan salt or sea salt.
And, not only do highly processed foods hit you with excessive amounts of sugar, salt and fat that cause weight gain, but they also don’t have the ingredients to help you stay healthy and active. While processed foods may contain the same amount of protein, fat or carbohydrates, they also contain fillers and additives. Whole fruits, vegetables, organic meats and nuts contain more quality vitamins, minerals and fiber. Even what we consider healthy “diet” foods, such as pre-packaged foods, powders and beverages, may have ingredients that are harmful in the long term.
Ultra-processed foods trigger hunger hormones
An NIH study tested 10 men and 10 women and found that levels of the appetite-stimulating hormone gastrin increased during the two weeks they ate ultra-processed foods compared to baseline. Levels of the appetite-suppressing hormone pancreatic peptide YY (PYY) increased during the two weeks of eating unprocessed foods. After two weeks, participants who received the ultra-processed diet received the unprocessed diet first, while participants who received the unprocessed diet received the ultra-processed diet. PYY increased when participants received the unprocessed diet, while Ghrelin increased in participants who switched to the ultra-processed diet.
Additives in ultra-processed foods cause inflammation in the gut
When researchers fed healthy mice polylactide-80 and carboxymethylcellulose, two emulsifiers often found in ultra-processed foods, the mice ate more and gained weight. They developed metabolic syndrome and had difficulty regulating their blood sugar. When researchers examined the intestinal tissue of these animals under a microscope, they saw signs of mild inflammation. The emulsifiers promoted the growth of harmful bacteria in the gut that could digest the mucus lining in the intestine or grow close to the intestinal tissue itself.
The findings add to the growing body of evidence that bacteria living in the human body, including the gut microbiome, play an important role in overall health. It is worth noting, however, that while eating large amounts of ultra-processed foods can lead to significant weight gain, so can gastrointestinal disorders such as gastroesophageal reflux (or GERD), ulcers and Crohn’s disease.
Excess of Toxicity
Processed foods may contain chemicals that our bodies have to work to get rid of. This can place a burden on our filtering organs such as the kidneys or liver. Processing toxic overload may create stress, which increases cortisol and subsequently insulin. Just as a lack of nutrients can block important bodily processes, toxins can also block or impede reactions.
The oxidation (cellular damage) that occurs with toxins can lead to inflammation, forcing the body to maintain excess water, which can also manifest as weight gain.
Ultra-processed foods are linked to depression
Researchers from Spain and Brazil found that 774 of the nearly 15,000 adults in Spain developed depression during the approximately 10-year study follow-up period. Those who ate ultra-processed foods most often had a 33 percent higher risk of depression than those who ate ultra-processed foods least often. The risk of depression was greater among those who reported low levels of physical activity. In a 2018 study, depressed participants who also had increased appetite had significant immunometabolic dysregulation, including insulin resistance, which was associated with weight gain.
Practical Solutions for Avoiding Highly Processed Foods
While we are still learning about the effects of processed foods on the body, there is no doubt that whole foods are better. If you want to manage your weight more effectively, cutting out processed foods is a good first step.
This may seem easier said than done. Processed foods are prevalent for a reason. If you have a full schedule or tight budget, you may already feel like eating a whole foods diet is impractical. However, there are always small changes you can make today to build a long-term healthy diet. For snacks, choose nuts, vegetables or fruit instead of chips or cookies. For sandwiches, replace highly processed, nitrate-filled packaged deli meats with leftover chicken from dinner. Start your day with eggs instead of a sugar-laden breakfast bar.