The oft-embraced "cheat day" is a common theme in many diets and the popular ketogenic diet is no exception. But new research says that just one 75-gram dose of glucose — the equivalent of a large bottle of soda or a plate of fries — while on a high-fat, low-carb diet can lead to damaged blood vessels.
For their test, the researchers recruited nine healthy young men and had them consume a 75-gram glucose drink before and after a seven-day high-fat, low-carb diet. The diet consisted of 70 percent fat, 10 percent carbohydrates and 20 percent protein, comparable to that of a modern ketogenic diet.
"We were originally looking for things like an inflammatory response or decreased tolerance to blood glucose," the researcher says. “What we found instead were biomarkers in the blood, suggesting that vessel walls were damaged by the sudden spike in glucose.”
The researcher says the most likely culprit for the damage is the body's own metabolic response to excess blood sugar, which causes blood vessel cells to shed and possibly die.
“Even though these were otherwise healthy young men, when we looked at the health of their blood vessels after consuming the glucose drink, the results appeared to be from someone with poor cardiovascular health,” the researcher added. “It was somewhat alarming.”
“My concern is that many people going on a keto diet — whether it's to lose weight, to treat type 2 diabetes, or for any other health reason — may be seeing some of the positive effects on their blood vessels. undo them when they suddenly skyrocket with glucose,” he says. “Especially if these people have a higher risk of cardiovascular disease in the first place.”
“Our data suggests that a ketogenic diet isn't something you do six days a week and then take Saturday off.”
