Think twice before you make that a lifestyle — a small, preliminary study published in the February 2019 issue of Nutrients suggests that a cheat day on keto may actually damage blood vessels. RELATED: 8 Steps Beginners Should Take Before Trying the Keto Diet
How Researchers Studied the Effects of Keto on the Blood Vessels
In the study, nine healthy men drank a solution containing 75 grams (g) of glucose and had blood and vascular testing done to assess their response to the high-sugar drink. They then received meal plans and packaged food and followed a ketogenic diet for seven days. The diet was made up of 70 percent of calories from fat, 20 percent from protein, and 10 percent from carbohydrates. This was enough time that their bodies began to burn ketones for fuel rather than relying on carbs for energy, which is what your body typically does. Yet while they were somewhat in ketosis, they were likely not fully “keto-adapted” after just one week, the researchers say. The body becomes keto-adapted when it becomes trained to depend on fat instead of carbs. After the week on the diet, they came off on day eight by drinking another 75 g glucose drink. (For reference, those on keto often eat just 20 to 50 total g of carbs a day.) Following additional blood work, researchers analyzed various health markers indicating inflammation or impaired glucose tolerance. What they found was evidence that endothelial cells, which line blood vessel walls, had been damaged. “The endothelial cells lining the blood vessels are exposed to everything that circulates in the blood. They take up glucose in direct proportion to its concentration in the blood in a sort of unregulated fashion,” says the senior author of the study, Jonathan P. Little, PhD, an assistant professor at the University of British Columbia Okanagan in Kelowna. “Based on studies of endothelial cells in culture, the surge in glucose causes an increase in oxidative stress that damages the cells and impairs their function,” he says. RELATED: What Are the Health Benefits and Risks of the Keto Diet?
Why We Need More Research on the Cellular Effects of the Keto Diet
The long-term implications are unclear. The damage seen was “transient,” says Dr. Little. “It only lasted for the hour or so when glucose was spiked and then went back to baseline,” he says. Therefore, it’s not known how these effects may compound over time if, say, someone was following a keto-cheat day pattern for six months or longer. Also important is maintaining perspective. This was a study on nine males. It wasn’t a representative sample involving women and people of varying ages. Also consider that these participants were only on a keto diet for a week. For people who were on it for longer and thus fully keto-adapted, their results may be worse. “I would anticipate that the impaired glucose tolerance in a previously healthy insulin-sensitive person following a long-term ketogenic diet would be even more pronounced, and the surge in glucose might be even more damaging — but we cannot confirm this in our study,” says Little. But Little also points out that the risks of this blood vessel damage may not outweigh the benefits of potential weight loss and blood sugar control in those following keto who are obese or have type 2 diabetes. Early research, including a study published in September 2018 in the journal Expert Review of Endocrinology & Metabolism, suggests the keto diet can help obese people lose weight and those with type 2 diabetes better control their blood sugar. “These benefits of the ketogenic diet for reducing their overall risk of cardiovascular disease are likely to outweigh the small increase in blood vessel damage they might incur on a ‘cheat day,’” Little says. Although researchers don’t know how the keto diet affects heart disease risk in the long term, the American Heart Association notes that being overweight or obese, or having diabetes, are risk factors for this health condition. RELATED: 11 Health Conditions Keto May Help — and 6 It Won’t
What to Take Away From the Study if You’re Considering the Keto Diet
The ketogenic diet is hotly contested right now. Originally, scientists created a strict version of keto to help control seizures in children with epilepsy — something it does well, according to the Epilepsy Foundation. Since then, it’s been co-opted as a fad diet, but highly criticized because it lacks long-term studies on its efficacy and safety as a weight loss diet. If you’re on keto, this research might be a bit of a wake-up call. “Keto is not a diet that you can do halfway. To stay in ketosis, you have to commit to it. You either keto or you don’t,” says Amy Kubal, RDN, a registered dietitian in Sioux Falls, South Dakota. When you overload your body with a sudden dump of glucose — as is what happens on a cheat day — the resulting blood sugar spike essentially throws your body a curveball. An unexpected surge of carbs at this time can affect your digestion, and make you fatigued, among other ills, and it may put you at risk for health problems down the line, says Kubal. “If you need a cheat day, keto is not right for you. You need to find a way to eat that fits your lifestyle and needs,” she says. That’s the advice she gives anyone on any diet when it comes to cheat days: Just don’t. “A better idea is to find a way to fit the foods you enjoy into your regular, everyday diet,” says Kubal. RELATED: 10 Popular Low-Carb Diets, and Their Pros and Cons
title: “A Cheat Day On The Keto Diet May Harm Blood Vessels Study” ShowToc: true date: “2022-11-29” author: “Kathy Moulton”
Think twice before you make that a lifestyle — a small, preliminary study published in the February 2019 issue of Nutrients suggests that a cheat day on keto may actually damage blood vessels. RELATED: 8 Steps Beginners Should Take Before Trying the Keto Diet
How Researchers Studied the Effects of Keto on the Blood Vessels
In the study, nine healthy men drank a solution containing 75 grams (g) of glucose and had blood and vascular testing done to assess their response to the high-sugar drink. They then received meal plans and packaged food and followed a ketogenic diet for seven days. The diet was made up of 70 percent of calories from fat, 20 percent from protein, and 10 percent from carbohydrates. This was enough time that their bodies began to burn ketones for fuel rather than relying on carbs for energy, which is what your body typically does. Yet while they were somewhat in ketosis, they were likely not fully “keto-adapted” after just one week, the researchers say. The body becomes keto-adapted when it becomes trained to depend on fat instead of carbs. After the week on the diet, they came off on day eight by drinking another 75 g glucose drink. (For reference, those on keto often eat just 20 to 50 total g of carbs a day.) Following additional blood work, researchers analyzed various health markers indicating inflammation or impaired glucose tolerance. What they found was evidence that endothelial cells, which line blood vessel walls, had been damaged. “The endothelial cells lining the blood vessels are exposed to everything that circulates in the blood. They take up glucose in direct proportion to its concentration in the blood in a sort of unregulated fashion,” says the senior author of the study, Jonathan P. Little, PhD, an assistant professor at the University of British Columbia Okanagan in Kelowna. “Based on studies of endothelial cells in culture, the surge in glucose causes an increase in oxidative stress that damages the cells and impairs their function,” he says. RELATED: What Are the Health Benefits and Risks of the Keto Diet?
Why We Need More Research on the Cellular Effects of the Keto Diet
The long-term implications are unclear. The damage seen was “transient,” says Dr. Little. “It only lasted for the hour or so when glucose was spiked and then went back to baseline,” he says. Therefore, it’s not known how these effects may compound over time if, say, someone was following a keto-cheat day pattern for six months or longer. Also important is maintaining perspective. This was a study on nine males. It wasn’t a representative sample involving women and people of varying ages. Also consider that these participants were only on a keto diet for a week. For people who were on it for longer and thus fully keto-adapted, their results may be worse. “I would anticipate that the impaired glucose tolerance in a previously healthy insulin-sensitive person following a long-term ketogenic diet would be even more pronounced, and the surge in glucose might be even more damaging — but we cannot confirm this in our study,” says Little. But Little also points out that the risks of this blood vessel damage may not outweigh the benefits of potential weight loss and blood sugar control in those following keto who are obese or have type 2 diabetes. Early research, including a study published in September 2018 in the journal Expert Review of Endocrinology & Metabolism, suggests the keto diet can help obese people lose weight and those with type 2 diabetes better control their blood sugar. “These benefits of the ketogenic diet for reducing their overall risk of cardiovascular disease are likely to outweigh the small increase in blood vessel damage they might incur on a ‘cheat day,’” Little says. Although researchers don’t know how the keto diet affects heart disease risk in the long term, the American Heart Association notes that being overweight or obese, or having diabetes, are risk factors for this health condition. RELATED: 11 Health Conditions Keto May Help — and 6 It Won’t
What to Take Away From the Study if You’re Considering the Keto Diet
The ketogenic diet is hotly contested right now. Originally, scientists created a strict version of keto to help control seizures in children with epilepsy — something it does well, according to the Epilepsy Foundation. Since then, it’s been co-opted as a fad diet, but highly criticized because it lacks long-term studies on its efficacy and safety as a weight loss diet. If you’re on keto, this research might be a bit of a wake-up call. “Keto is not a diet that you can do halfway. To stay in ketosis, you have to commit to it. You either keto or you don’t,” says Amy Kubal, RDN, a registered dietitian in Sioux Falls, South Dakota. When you overload your body with a sudden dump of glucose — as is what happens on a cheat day — the resulting blood sugar spike essentially throws your body a curveball. An unexpected surge of carbs at this time can affect your digestion, and make you fatigued, among other ills, and it may put you at risk for health problems down the line, says Kubal. “If you need a cheat day, keto is not right for you. You need to find a way to eat that fits your lifestyle and needs,” she says. That’s the advice she gives anyone on any diet when it comes to cheat days: Just don’t. “A better idea is to find a way to fit the foods you enjoy into your regular, everyday diet,” says Kubal. RELATED: 10 Popular Low-Carb Diets, and Their Pros and Cons
