The 1 Unexpected Side Effect Of Rapid Weight Loss We Don't Talk About Enough

For generations, people have been told they need to look a certain way and weigh a certain amount to be accepted and to be considered “healthy.” But we know that being thin isn’t an indicator of well-being.

“It’s actually a major talking point I would say in the obesity community now ... what are the unintended consequences of weight loss?” said Dr. Kurt Kennel, a bariatrician and endocrinologist at the Mayo Clinic in Rochester, Minnesota.

One of those consequences was detailed by actor Jameela Jamil, who recently shared on Instagram that years of extreme dieting and weight loss had harmed her bone density.

“So much chat about the dangers of eating too much and crickets when it comes to the long term impact of eating too little,” Jamil wrote. Jamil, who is 38, said that she damaged her bone density through 20 years of extreme dieting and is now dealing with consequences such as pain.

Though bone density isn’t talked about very much in day-to-day life, it’s an important measure of health. Bone density is how much mineral content is present in your bone, explained Dr. Gillian Wooldridge, a sports medicine physician at Houston Methodist Hospital.

“If you have higher bone density, it generally means you have denser ― and for the most part, healthier ― bones that are more resistant to fracture or breaking,” Wooldridge said. “If you have thinner bone density, it means you don’t have as much good structure there and you could be at increased risk for fracture.”

Our bone density peaks around 25-years-old, said Kennel, “and then we hope to maintain that through most of our midlife until our 50-ish year of age or so. Because after that we start to lose it as part of menopause, we start to lose it as part of ageing.”

This is one reason why falls for older people are often a huge deal, resulting in things like hip fractures or other broken bones. Your bone density is measured via a bone density test, generally starting at age 65, though it may be recommended earlier to women during menopause. 

“We want to hang on to that peak bone density, we want to maintain that as long as we can, or at least not do anything to aggravate losing it beyond things we can’t control, like menopause and ageing, for example,” Kennel said.

One way we also lose it is through significant weight loss, like Jamil said. Here’s what experts want you to know:

Weight loss can harm bone density, but extreme weight loss and crash diets are the most damaging

“Weight loss can decrease bone density, both for people who become underweight but also for overweight people who lose a significant amount of weight,” Dr. Deborah Sellmeyer, a clinical professor of medicine in endocrinology, gerontology and metabolism at Stanford University, told HuffPost via email.

Research shows that bone density loss is less prevalent and harmful in folks who lose a moderate amount of weight in a healthy manner — although some experts say it does still happen. “Even if we’re doing healthier approaches, there’s still some of that weight loss that is not fat. Some of that weight loss will always be muscle and, especially in the case of menopausal women, bone,” Kennel said.

Wooldridge stressed that extreme dieting and rapid weight loss pose the biggest threat to your bone density. 

“Rapid weight loss, severe calorie restriction or some sort of other significant energy deficit ... sometimes they make up for what they eat by exercising excessively. Any of those states are potentially going to have a negative impact on bone density,” Wooldridge said.

It’s worth noting that extreme weight loss from disordered eating or a medical procedure, such as gastric bypass, can have a negative impact on bone density, too, Wooldridge added.

Resistance training and proper nutrition can help you maintain bone density while losing weight

“We can say with confidence that when we incorporate exercise into the weight loss process, especially resistance exercise at the end of the weight loss ... by having that exercise in the picture throughout that process, we will lose less muscle and less bone than if we just restrict our calorie intake [or] just lose weight by cutting back on eating,” Kennel said.

Resistance training includes push-ups, lunges, squats, weightlifting — “anything that involves your muscles having to work against resistance ... you’re pulling something, you’re pushing yourself up, you’re pulling yourself down. Anything that has that kind of quality to it,” he said.

What you’re eating can help you maintain bone density, too.

“Nutrition is very important for bone health, so food intake is important, but so is ensuring adequate intake of calcium, vitamin D and protein,” Sellmeyer said.

“We generally consider ‘healthy weight loss’ or sustainable weight loss to be at the rate of about a half pound to a pound per week,” Wooldridge said. “So, for someone who is engaging in a weight loss program, that is a pretty good goal; that means that’s going to be weight that you lose that you can keep off.”

Unsustainable weight loss ― losing and gaining weight over and over ― tends to put a strain on the body, she added.

This may be particularly relevant now in the world of GLP-1 medications, such as Wegovy and Ozempic, which many people now use to lose weight. Though there are benefits for many folks, some research says these medications can decrease bone density and muscle mass, too. They’re also a concern for people who are at risk of developing osteoporosis.

The idea that you need to lose weight to be healthy is wrong

“This issue of losing muscle and losing bone, you don’t tolerate that as well when you’re 80 [or] 70, versus when you’re 30, partly because the 30-year-old will be able to do more to attenuate that by doing a lot of exercise, for example, whereas the 80-year-old, may not be able to do that as much,” Kennel explained.

Weight loss for someone in their 70s or 80s may not have the same health benefits as for someone in an earlier stage of life, he noted. So all of those diet culture messages to slim down no matter your age aren’t totally fair.

“I tell people all the time, a number on a scale is a number on a scale. It’s not a score for how you’re doing or has anything to do with your value,” Wooldridge said “And it also doesn’t necessarily reflect health. It is simply a number on a scale.”

It’s more important to think about how you’re living your life. Are you exercising regularly? Are you eating a diet made up of fruits, vegetables, lean proteins, healthy fats and whole grains? 

“I care about that so much more than a number on a scale, and a number on a scale is really not a reflection of someone’s overall health,” she said.

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