Overeating during the holidays is bad for your kidneys

Given all of the delicious foods that are served during holiday meals, many people find it hard to resist eating more than they usually would. But what you may not think about is what all of that extra food is doing to your kidneys. Baylor College of Medicine's Dr. Sreedhar Mandayam explains how overeating during the holidays can impact your kidneys.

"The body absorbs nutrients from the gut and then the liver metabolizes them. Whatever is left that can't be used by the body is excreted by the kidneys," said Mandayam, associate professor of medicine in the section of nephrology. "The more you eat, the more you deliver to your kidneys to excrete, so eating a lot of substances that are very high in proteins or toxins can put a strain on your kidneys because they now have to handle the excess calories, toxins or proteins you've eaten."

During holidays like Thanksgiving, people tend to eat very heavy meals with lots of proteins and carbohydrates, and this can impact not only kidney function, but also liver, pancreas and cardiac function, Mandayam said.

When you consume carbohydrates, the body will use what is necessary for immediate energy release but any extra carbohydrates are converted into fat and stored underneath the skin and in the muscles and the liver. Similarly, when you eat a lot of fat, if the fat can't immediately be converted into energy-producing adenosine triphosphate, then all of the fat will be stored in various fat deposits in the body, Mandayam explained.

The building up of fat inside your liver can lead to liver failure or cirrhosis, and fat inside your blood vessels can lead to heart attacks. Additionally, eating a lot of protein that your body can't metabolize can lead to an increase in blood urea nitrogen, which adds stress on kidneys because they have to work harder to excrete this.

It is especially important for people with chronic kidney disease and kidney stones to not overeat, he said.

"For people with kidney disease, even eating normal amounts of food puts stress on their kidneys," he said. "If you consume large amounts of carbohydrates, protein or fat the stress on an overworked, half functioning kidney will get even worse and can accelerate your kidney dysfunction."

Kidney stones form when salts crystalize because you have an imbalance between the salt and water that can't be dissolved in your urine, Mandayam said. When you eat heavy meals, you may eat a lot of substances that cannot be dissolved and kidney stones can form.

"It is very common after the holidays for us to see people coming in with new stones or stones that have previously been smaller but have grown in size and are causing obstructions or pain," Mandayam said.

You should enjoy the holidays but eat in moderation, he said.

"Most people don't need to consume more than 2,500 calories per day, and try not to have more than 30 percent of that be carbohydrates and only have about a gram of protein per day. Staying hydrated also is one of the best ways to maintain your kidney health," Mandayam said.