"There needs to be a massive public health initiative to educate people about the need for improved nutrition in the midst of the pandemic," said Dr. Mark Hyman, a New York Times bestselling author and the head of strategy and innovation at the Cleveland Clinic Center for Functional Medicine. "I think that this is such a critical moment and it's central for us to double down on our nutritional quality in our diet, people are completely neglectful that it is a way of preventing COVID-19."
A published peer-reviewed study showed the changes in dietary habits during the pandemic. Since March, there have been increased purchases of processed shelf-stable foods, calorie-dense comfort foods, alcohol and takeout orders. In addition, the authors of the study used Google Trends data that showed increases in searches for restaurants and baking, with a decline in searches for "healthy eating," which typically rise after the holiday season.
"I think the habits that we're seeing people adopt as a society [create] the perfect equation for long-term health consequences," said Brigid Titgemeier, a functional medicine dietitian and the founder of beingbrigid.com, a nutrition website.
She said that the types of foods people seem to be indulging during this time could not only hurt their waistlines, but also their chances of fighting the virus should they become sick.
"Empty calories mean higher glycemic carbohydrates that increase blood sugar levels, added sugars that lower immune function, low fiber that impairs the gut microbiome," she said. "Paired with sedentary lifestyles, stress and anxiety, it really creates the perfect storm to increased rates of obesity and cardiometabolic diseases, which have been linked to higher rates of death from COVID-19."
The appeal of comfort foods has led to adopting destructive behaviors to cope, like overconsumption of alcohol and overeating unhealthy foods, said Dr. Jasmol Sardana, a lifestyle medicine physician at the Barnard Medical Center. She further explained that external stressors such as loss of jobs, the troubles of working from home, child care, schooling responsibilities and the anxiety from the virus itself, can cause individuals to gravitate towards binge eating and emotional eating for comfort, which can lead to severe health issues.
Eating healthy can reverse chronic conditions like hypertension, diabetes and high cholesterol. And experts are pointing out that those improvements could, in turn, help give people's immune systems a boost.
"Eating a diet that is naturally nutrient-dense and low in calories drastically decreases one's risk of obesity, diabetes, high cholesterol, hypertension and some cancers," said Sardana. "Beyond that, our immune system and our mental health are best supported when we choose whole foods and plants as well."
Many doctors, such as Klodas, encourage their patients to think of "food as medicine."
Her research group found that people with high cholesterol who followed her "Step One" foods program -- a month-long diet which combines a person's normal diet with additional foods rich in antioxidants and anti-inflammatory nutrients -- can see their "bad" cholesterol lowered an average of 9%. Some see it lowered up to 40%.
"When we created Step One foods, it was really to take that concept of food as medicine and translate it into an actual practical thing," Klodas said. "It is designed specifically to address hyperlipidemia. Every single ingredient was chosen for its cholesterol-modifying or health-promoting properties based on extensive research."
The ability to prevent illness through food by strengthening immunity is not a novel idea. Research shows that the "Western diet" -- especially foods like processed meat, refined grains and those pre-packaged foods with added preservatives -- causes chronic inflammation and suppresses other aspects of the immune system which help fight viruses like COVID-19.
"I try to help my patients understand that it's not just about the weight," said Hyman. Through poor nutrition, "they're increasing their risk of complications and severe infection from COVID-19."
He further explained that the consumption of ultra-processed foods -- which reportedly make up about 60% of the Western diet -- the added sugars and the starches are all contributing to this inflammation, which experts agree a person should want to avoid, especially now that COVID-19 infection is still a major risk.
With high-nutrient foods, one can not only suppress inflammation, but also strengthen their body's immune response. The CDC says that these micronutrients are best consumed through food, rather than through supplements.
Titgemeier agrees that eating healthy food works much better than taking vitamins. She said scientists and doctors are just starting to understand how people's microbiomes -- the billions of bacteria that live within each human body -- contribute to this complex balance of nutrition and health.
"From an immune health standpoint, optimizing gut health is vital because the microbes house 70% of your immune system. You can create a more thriving gut environment through eating a lot of fiber in the diet, eating probiotic rich foods, and eating prebiotic rich foods," she said.
Stress about the pandemic has affected many, but both Titgemeier and Hyman believe there are steps people can take to improve their outlook.
"It is easy to focus on the downsides of the pandemic, but you can focus on the positives, which is more time at home and less traveling for those who travel for work," Titgemeier said. "Now, they have the opportunity to actually control the ingredients in their food."
Hyman said there are many things people can do to change their diets and reverse the effects of the "Quarantine 15." He said the first step should be to seek whole, nutrient-dense foods, such as fruit, vegetables, nuts, seeds, beans and high-quality protein. Second, he said people should eliminate ultra-processed foods. Third, people should try to focus on eating foods with high nutritional density, such as sardines and mushrooms for sources of Vitamin D, or pumpkin seeds for zinc.
He said that eating nutrient-rich, high-quality foods can be expensive -- a luxury that not everyone can afford. Still, there are resources available for people trying to eat healthy on a tighter budget.
"A great source is The Environmental Working Group. They talk about how to eat well for you, your planet and your wallet," Hyman said. "I think that it is important that people understand that the whole notion that eating is expensive, takes too much time and it is too difficult, is propaganda that impedes people from actually taking control of their own health and their diet."
During the pandemic, Klodas explained, people have control over how they maintain social distancing, whether they choose to wear masks and how often they wash their hands, but they can take their health a step further by following a nutrient-rich diet to make their immune systems more resilient.
Lily Nedda Dastmalchi, D.O., M.A., is an internal medicine resident physician at The George Washington University, and a contributor to the ABC News Medical Unit.