One of my patients—who had been struggling with obesity, uncontrolled diabetes, and the cost of her medications—agreed in June 2019 to adopt a more whole-food, plant-based diet. Excited by the challenge, she did a remarkable job. She increased her fresh fruit and vegetable intake; stopped eating candy, cookies, and cakes; and cut down on foods from animal sources. Over six months, she lost 19 pounds and her HbA1c—a measure of average blood sugar—dropped from 11.5 percent to 7.6 percent. She was doing so well, I expected that her HbA1c would continue to drop, and she would be one of our plant-based successes who had reversed diabetes. Her three-month follow-up visit in March 2020 was canceled because of the COVID-19 lockdowns. When I eventually saw her again in May 2021, she had regained some of the weight and her HbA1c had climbed to 10.4 percent. She said her diabetes doctor and …