| I love burgers, and in the past, there were occasions when I ate them multiple times a week. But in recent years I’ve focused on healthier eating, which has helped lessen some of my long Covid symptoms such as extreme fatigue. This has also meant that burgers are now only an occasional treat. For a while, I substituted meat patties with plant-based versions that are designed to look and taste like beef. They were delicious, but I was concerned when an app I use to track my long Covid symptoms showed a drop in my heart rate variability the morning after eating one of these burgers. (I ate several more to test that this wasn’t a one-off occurrence.) Drinking alcohol can also lower heart rate variability. Also known as HRV, it measures the variation in time between each heartbeat. This variation is controlled by the autonomic nervous system and research suggests that reduced HRV can predict the fatigue severity of people suffering from energy-limiting conditions such as chronic fatigue syndrome. As a result of this HRV conundrum, I decided to do a little more research into plant-based burgers and found that while they don’t contain meat, they do tend to be highly processed. The World Health Organization’s regional office for Europe funded a study into the food products, which involved conducting a laboratory analysis to determine the nutritional composition of plant-based burgers purchased in Amsterdam, Copenhagen, Lisbon and London. The results published last year indicate that while ultra-processed plant-based burgers are a source of (low-quality) protein, dietary fiber and essential minerals, they also contained relatively high levels of sodium, total fat and saturated fatty acids. The study didn’t compare how these plant-based burgers stack up against meat versions. Of course, when considering different diets, research has found that plant-based alternatives that mimic meat are associated with lower cholesterol, fat and calories when compared to animal products, and can also be beneficial for gut health. And although many of the food products are high in sodium, latest data suggests they don’t seem to negatively affect cardiovascular risk factors such as blood pressure, according to a literature review published in the Canadian Journal of Cardiology last year. Plant-based meat alternatives “can be an especially helpful bridge for those who are trying to reduce meat consumption,” says Rohini Bajekal, a nutritionist and communications lead at Plant-Based Health Professionals UK. For people wanting to avoid ultra-processed food in a plant-based diet, Bajekal recommends adding whole food protein sources such as tofu and tempeh, which are both made from soybeans. When it comes to plant-based burgers, look for those made with whole foods like beans as they usually have less sodium, are higher in fiber and typically much lower in saturated fat. Despite my efforts, I couldn't find any published studies looking at links between plant-based burgers and HRV, so I can’t draw any conclusions about whether there really is a connection between the two. It’s possible that my experience was an isolated case related to my long Covid condition, which can make me more sensitive to what I consume. These days, I’m not too alarmed if my HRV drops outside its normal range for a day or two, given my overall energy levels seem to be improving thanks to lifestyle changes and other factors. Even so, I’ll try to take it easy on those days. When it comes to burgers, the next one I eat will probably be plant-based. —Lisa Pham | 
