Eating too many carbs in one meal can disrupt your metabolism

BOSTON, Mass. — Loading up on carbohydrates before a big run is time-honored tradition, but is it really a healthy one? A new study finds consuming a large number of carbs at one time can actually disrupt the body’s overall metabolic rate, causing metabolic dysfunction. Researchers from Harvard-affiliated Brigham and Women’s Hospital and Boston Medical Center found that eating too many carbs leads to the breakdown of powerful antioxidants, a process that gets worse when insulin production increases.

Metabolism affects every cell in the body. Since this process helps the body’s cells receive energy, it is crucial that nothing interrupts this process. However, previous studies have linked obesity to a decreased metabolism. The association of obesity with type 2 diabetes and insulin resistance also points to the consumption of carbs as a factor causing metabolic distress.

So far, research has revealed the effects of sugar intake on the body’s metabolism over time. Unfortunately, prior studies have failed to assess how large quantities of carbs affect overall metabolism if consumed at one time.

“When we treat people with type 2 diabetes, the focus is often on lowering blood sugar rather than preventing carbohydrate overfeeding, which is very common in our society,” says Nawfal Istfan, MD, Ph.D., of the Brigham’s Division of Endocrinology, Diabetes, and Hypertension, in a university release. “But our study shows that if overfeeding isn’t controlled, some of the traditional ways of treating diabetes, like giving patients more insulin to lower blood sugar, can potentially be more harmful.”

Carbs affecting the body at an atomic level?

Scientists conducted an investigation involving 24 women divided into two study groups: one group with a healthy body mass index (BMI) and one group with a high BMI in the overweight to obese range. None of these women had diabetes.

All participants ate a large number of carbs in one sitting. Some individuals ate more than 350g, or three-quarters of a pound worth of carbs. After analyzing blood and fat samples, researchers discovered that the antioxidant glutathione was being stripped of its electrons. Those with a higher BMI were more prone to this process, leading researchers to believe that cells were taking electrons from the antioxidant in order to fuel the process of fat conversion from carbs.

The fat samples from overweight participants also revealed decreased metabolic function compared to those with type 2 diabetes and insulin resistance. Since insulin increases the absorption of carbs by cells, it amplified the effects of metabolic dysfunction, due to cells being ill-equipped to deal with such a high volume of carbs.

Learning when to put down the fork

These results reinforced the theory that excess carbs could lead to a declining metabolism. Too many carbs force cells to store them as lipids, or fats. This process involves the conversion of carbs into fats, which requires electrons. According to the study, as excess fat is produced, electrons are stolen from other important metabolic processes, such as antioxidant generation.

This study’s quantitative technique is typical in the study of biochemical systems, but scientists seldom utilize it to explore brief activities like overeating. The team intends to employ this same technique in future studies to evaluate other cellular processes in people with average versus abnormal BMIs.

“The methodology we used in this study could be used in the future to explore individuals’ predispositions to weight gain,” Istfan says. “There are real differences between patients’ metabolisms, which is something that has been ignored in medicine. Metabolic overfeeding varies between patients, and we need to understand this so we can give more appropriate dietary advice.”

The study is published in the American Journal of Physiology-Endocrinology and Metabolism.