Does unintentional weight loss in middle age increase the risk of cancer? Research from Harvard University shows that this is the case

Although it may sound counterintuitive, losing weight can increase your risk of cancer, a study shows.

Harvard researchers found that health care workers in their 40s and older who lost more than one percent of their body weight had a 57 percent higher rate of cancer a year later than those who stayed the same weight.

The risk of cancer of the esophagus, stomach, liver, bile ducts or pancreas was also higher specifically.

Although the study needs further investigation, the academics say people should not be put off dieting in their 60s.

It may have been the cancer itself that caused the weight loss. When tumors begin to grow, especially in the digestive system, it can lead to loss of appetite.

The graph above shows cancer diagnosis rates (top lines) and death rates (bottom lines) for men (red) and women (blue) since the beginning of this century. This shows that mortality rates generally show a downward trend, while mortality rates are stable

And being obese has been linked to several common cancers, including breast, colorectal, esophageal, kidney, gallbladder, uterine, pancreatic and liver cancer.

Several previous studies have shown that losing weight actually reduces the risk of cancer.

The most recent study followed a group of female nurses aged 40 and older from 1978 to 2016, and a group of male healthcare professionals from 1988 to 2016, bringing the total participant pool to more than 157,000 participants.

Healthcare professionals were followed because the researchers said that “weight loss is common in primary care.”

The participants reported their weight every two years and were followed for an average of 28 years.

During the year after weight loss, there were 1,362 cases of cancer per 100,000 person-years among all participants who had recently lost more than 10 percent of their body weight.

This was compared with 869 cases of cancer per 100,000 person-years in people without recent weight loss.

This amounts to a 57 percent higher risk.

Cancer of the esophagus, stomach, liver, bile ducts, or pancreas was especially common in participants with recent weight loss.

There were 173 cases of this type of cancer per 100,000 person-years in those who had lost more than 10 percent of their body weight, compared with 36 cases of cancer per 100,000 person-years in those with no recent weight loss.

The researchers found that many other types of cancer, including breast, genital, urinary tract, brain and melanoma, were not associated with recent weight loss.

Participants with recent weight loss had a higher risk of a subsequent cancer diagnosis if they did not plan to lose weight but did exercise more and eat a healthier diet.

According to the American Cancer Society, unexplained weight loss is often the first noticeable symptom of cancer of the esophagus, pancreas, stomach and lungs.

The researchers also noted that many conditions, as well as cancer, can cause weight loss.

Their findings contradict much of the existing literature.

A 2023 study of nearly 600,000 people found that every five-point increase in body mass index (BMI) is associated with an 11 percent higher risk of obesity-related cancer, even in people without cardiovascular disease or type 2 diabetes.

A major study published last year by researchers at Newcastle University in Britain found that limiting fast food helps lower the risk of certain types of cancer.

Fast food has been linked to cancer because eating it in large quantities increases the risk of obesity. Being overweight can cause a host of hormonal changes that can cause tumors to grow.

A 2022 German study found that being overweight or obese at any time in life can increase a person’s risk of developing colorectal cancer over time, and the longer a person is overweight, the greater the risk becomes.

Another study from the American Cancer Society found that being overweight or obese is the second most common cause of cancer, after smoking.

It found that carrying excess fat, especially around the abdomen, is directly linked to 13 different types of cancer, including postmenopausal breast cancer, colorectal cancer and endometrial cancer.