The scary reason you might actually not want to lose weight as you get older

Fad diets that trigger extreme weight loss could be a waist for seniors, a new study finds.

Shedding pounds can be difficult as we age because our metabolism naturally slows, leading to fewer calories burned. You can also blame sarcopenia, the age-related loss of muscle mass, and hormonal shifts in women that influence fat storage.

It’s no wonder that older adults constitute a significant portion of users of GLP-1 drugs like Ozempic, which is prescribed to manage Type 2 diabetes and can bring major weight loss.

But remarkable new research out of Penn State University finds one major drawback to weight loss of more than 5% — it can fuel cognitive decline in adults over 65.

“Any way we looked at the data, the relationship was crystal clear — the more a person’s weight varied from year to year, the faster that person experienced cognitive decline,” said Muzi Na, an associate professor of nutritional sciences and senior author of the study. 

Na’s team tracked 4,300 older adults over 11 years, measuring their body composition and cognitive abilities such as memory, orientation and executive function.

The researchers crunched the data three ways. In one analysis, they looked at weight variations during the study period.

People with the smallest fluctuations had the least cognitive decline, the study showed, while participants with the greatest shifts in weight had two to four times as much cognitive decline.

The same results were found when researchers compared variability in waist circumference and body mass index to variability in cognitive decline.

In a third examination, the study authors linked losing at least 5% of body weight to faster cognitive decline.

Older adults who gained weight or whose weight remained stable in the meantime showed roughly the same level of cognitive decline.

“As people age, their cognitive ability tends to gradually decline,” Na said. “This is natural, and we saw that in this sample. But we also saw that people whose weight varied the most experienced more rapid cognitive declines.”

The findings were published recently in the journal Obesity.

Obesity, particularly in midlife, is a significant risk factor for cognitive decline. Excess fat tissue is a major contributor to chronic inflammation that can damage the brain.

Na noted there is an “obesity paradox” that suggests that late-life obesity can lead to better cognitive outcomes or a slower rate of cognitive decline.

“Some studies have revealed a complex interplay between age-related muscle mass loss and fat gain in older adults,” Na said.

She emphasized that her “study does not suggest older adults should gain weight.”

Instead, Na recommends monitoring weight at home instead of just at the doctor’s office for more reliable data.

“For example, a person could weigh themselves around the same time in the morning after getting up, before breakfast and after a bathroom trip while wearing the same pajamas,” Na said.

“This would provide them with very consistent data,” she added. “Then, if their weight is not stable, they need to let their physicians know.”