Lina Begdache, Assistant Professor of Nutrition, Binghamton University, State University of New York
If you experience unnecessary weight gain or weight loss during a pandemic, you are not alone. According to a poll conducted by the American Psychological Association, 61% of American adults have reported undesirable weight changes since the pandemic began.
Results released in March 2021
Another study, published on March 22, 2021, assessed the weight change of 269 people from February 2020 to June 2020. Researchers have found that people gain a steady 1.5 pounds per month on average.
I am a nutritional neuroscientist and my research investigates the relationship between diet, lifestyle, stress and mental distress (such as anxiety and depression).
Changes in stress (especially during a pandemic) are the main factors leading to weight changes. Another poll conducted by the American Psychological Association in January 2021 found that approximately 84% of American adults experienced at least one emotion related to prolonged stress in the first two weeks.
The discovery of unwanted weight changes is meaningful in a stressful world, especially in the context of the body’s stress response, which is called a fight or flight response.
Fighting, flying and food
The fight or flight response is an innate response, it is a survival mechanism. It enables humans to respond quickly to acute stress such as carnivores, or to chronic stress such as food shortages. When faced with stress, the body wants to keep the brain alert. It lowers the content of certain hormones and brain chemicals to reduce unhelpful behaviors in emergency situations, and it increases other hormones.
Under stress, the body reduces the levels of neurotransmitters (such as serotonin, dopamine, and melatonin). Serotonin regulates mood, appetite and digestion. Therefore, low levels of serotonin can increase anxiety and may change a person’s eating habits. Dopamine-another neurotransmitter that feels good-regulates goal-oriented motivation. A decrease in dopamine levels can reduce motivation to exercise, maintain a healthy lifestyle or perform daily tasks. When people are under stress, they also produce less sleep hormone melatonin, which leads to sleep difficulties.
Adrenaline and norepinephrine mediate stress-related physiological changes and increase under stress conditions. These biochemical changes can cause mood swings, affect people’s eating habits, reduce goal-oriented motivation and disrupt people’s circadian rhythms.
Overall, stress may make your eating habits and motivation for exercise or eating imbalance out of balance, and last year was undoubtedly a stressful year for everyone.
Low heat and low power
In both studies, people self-reported their weight, and the researchers did not collect any information about physical exercise. However, it can be prudent to assume that most weight changes are caused by people gaining or losing body fat.
So why did people gain or lose weight last year? How to explain these huge differences?
Many people find comfort in high-calorie foods. This is because chocolate and other sweets can make you happy by increasing serotonin levels in the short term. However, the blood will quickly clear the excess sugar, so the mental stimulation is extremely short-lived, causing people to eat more. Eating for comfort may be a natural response to stress, but when the motivation to exercise and eating low-nutrient, calorie-dense foods decreases, stress can lead to unnecessary weight gain.
How about losing weight? In short, the brain is connected to the intestines through a two-way communication system called the vagus nerve. When you are under stress, your body suppresses the signals that travel through the vagus nerve and slows down the digestion process. When this happens, people feel full.
This pandemic makes many people trapped in their own homes, feeling bored, having plenty of food, and distracting them. When you add a stress factor to this plan, you will experience the ideal situation of unwanted weight changes. Stress is always a part of life, but there are things you can do, such as practicing positive self-talk. These things can help resist stress reactions and some of their undesirable consequences.