Obesity can increase your chance of kidney stones. Experts don’t know exactly why this is, but losing weight may help lower your chance of developing them.

Obesity is a chronic health condition characterized by having a high amount of body fat. Its prevalence is increasing in the United States, with health survey data finding that the rate of obesity increased from 30.5% in 1999–2000 to 41.9% in 2017–2020.

Having obesity increases the chance of a range of health conditions. Some examples include diabetes, heart disease, and certain types of cancer.

People with obesity may also be at higher risk of developing kidney stones. This article takes a closer look at the link between obesity and kidney stones.

Kidney stones are hardened bits of material that can form in your kidneys from chemicals present in urine. They’re quite common, affecting an estimated 11% of people over the course of their lifetime.

Previous studies have shown that having obesity increases kidney stone risk. This goes for people with metabolically healthy obesity as well. That said, a 2023 study found that kidney stone risk was significantly higher when metabolic dysfunction occurred with obesity.

Experts don’t know exactly why obesity increases the chance of kidney stones. Additionally, the fact that many people with obesity have other health conditions as well makes the connection harder to confirm.

Researchers have proposed several theories about why obesity may contribute to kidney stone formation, including the following:

Kidney stones happen when chemicals in your urine harden and form pebble-like deposits. There are several types of kidney stones, but those made from calcium oxalate or calcium phosphate are the most common.

In addition to obesity, several other factors can increase your chance of kidney stones. These include having:

Taking certain medications can also increase your kidney stone risk. Some examples include diuretics and calcium-based antacids.

Eating a diet high in animal proteins or salt may also increase your likelihood of kidney stones. Cutting back on these can lower your chance of kidney stones, particularly if you’ve previously had them.

The following are some commonly asked questions about obesity and kidney stones.

Can losing weight get rid of kidney stones?

It’s possible that losing weight could help reduce kidney stone risk. For example, a 2015 study in rats found that weight loss through diet and exercise reduced kidney stone formation.

Additionally, a 2023 review noted that dietary weight loss strategies may help reduce kidney stone risk. However, the researchers noted that evidence for this is still limited and that more research is needed.

Does cutting weight cause kidney stones?

It’s also possible that losing weight may elevate your kidney stone risk in some cases. However, research on this topic is limited. Using extreme diets or certain types of fad diets to lose weight may increase kidney stone risk.

A 2023 study found that bariatric surgery was associated with an over six-fold risk of kidney stones afterward. However, the authors noted that this was likely due to physiological changes associated with the surgery and not the weight loss itself.

Can weight loss medications cause kidney stones?

Some weight loss medications can increase kidney stone risk. One 2020 review notes that these include orlistat (Alli) and phentermine-topiramate (Qsymia).

Can kidney stones make you lose weight?

Kidney stones themselves don’t lead to weight loss. However, certain lifestyle changes — such as those to your diet — can help prevent additional kidney stones from forming as well as promote weight loss.

Obesity increases the chance of kidney stones. However, experts don’t know exactly why this is. It’s likely that the effects of obesity on inflammation, oxidative stress, and urine composition play a role.

In addition to obesity, several other factors also elevate kidney stone risk. These include, but aren’t limited to, a personal or family history of kidney stones, a diet high in salt or animal proteins, and various health conditions.

If you have obesity, losing weight may help lower your chance of kidney stones. Be sure to talk with your doctor about developing a weight loss strategy that’s safe and that meets your needs.