Weight loss can weaken your bones. Here’s how to keep them strong.

Weight loss can improve your health in many ways. But it can also come with some drawbacks, like bone loss. Losing too much bone can make your bones weaker and raise your risk of fractures.

The good news is that there are steps you can take to help protect your bones during weight loss. GoodRX, a platform for medication savings, explains why bone loss can happen, how glucagon-like peptide-1 (GLP-1) medications may play a role, and what you can do to keep your bones healthy and strong.

Key takeaways:

• It’s normal to lose some bone when you lose weight, whether through diet, medication, or weight loss surgery.
• Glucagon-like peptide-1 (GLP-1) medications like Wegovy and Zepbound are linked to bone loss. But research suggests that weight loss itself, rather than the medication, causes most of this change.
• Strength training, regular exercise, and getting enough protein, calcium, and vitamin D can help protect your bones while you lose weight.

Is it normal to lose bone mass as you lose weight?

Yes, some bone loss is normal when you lose weight. Bone loss happens whether you lose weight through diet and exercise, medication, or weight-loss surgery.

But losing some bone density doesn’t mean you’ll definitely develop weak bones or have a fracture. Your risk becomes greater if you lose a lot of bone mass during weight loss.

Some people are more likely to lose more bone during weight loss. Your risk may be higher if you:

• Are an older adult
• Have gone through menopause
• Already have osteopenia or osteoporosis
• Have had a fracture caused by weak bones
• Lose a large amount of weight
• Don’t get enough calcium, vitamin D, or protein
• Don’t get regular exercise
• Have another health condition that can weaken your bones
• Take a medication that can weaken your bones

This doesn’t mean that losing weight is bad for your bones. But it does mean that protecting your bones should become part of your weight loss and health plan.

Why does bone mass decrease with weight loss?

Weight loss affects your bones in several ways at the same time:

• Your bones carry less weight. Your bones respond to the amount of weight and pressure placed on them. A higher body weight puts more pressure on weight-bearing bones, which signals your body to keep them strong. As you lose weight, your body may respond by building less bone and breaking down more bone.
• You lose some muscle, too. Weight loss doesn’t only come from body fat. Some of the weight you lose comes from muscle and other tissue. Your muscles pull on your bones when you move, which helps keep bones strong. Losing muscle means your bones get less of this healthy pressure.
• Your hormone levels change. Fat tissue helps make and control several hormones that affect your bones. Losing body fat can change your hormone levels and may cause your body to break down more bone than it replaces.
• You may get fewer bone-building nutrients. Eating less food can make it harder to get enough calcium, vitamin D, and protein. Your body needs these nutrients to maintain strong bones and build new bone.

Together, these changes can cause your body to break down bone faster than it builds new bone. That’s why protecting muscle and getting enough exercise and nutrients can be an important part of protecting your bones.

Do weight loss medications cause bone loss?

Yes, some bone loss can happen when you lose weight with medications like semaglutide (Wegovy) or tirzepatide (Zepbound). Research suggests that people who lose more weight with these medications also tend to lose more bone.

But the amount of bone loss is similar to what happens with nonsurgical weight loss. This suggests that weight loss, rather than the medication itself, is what’s causing bone loss.

So far, there isn’t enough research to know whether one weight loss medication causes more bone loss than another. Researchers are also studying amylin-combination weight-loss medications. Amylin is a peptide that may slow bone breakdown and support new bone growth during weight loss.

Can you prevent bone loss as you lose weight?

There aren’t specific guidelines for protecting bone health while losing weight with a GLP-1 medication. But experts agree that people taking GLP-1 medications should prioritize exercise and good nutrition. Some people may also need to have their bone health monitored. Talk with your healthcare team about a bone health plan while taking a GLP-1 medication, especially if you:

• Lose more than 10% of your body weight
• Are an older adult
• Have gone through menopause
• Already have osteopenia or osteoporosis
• Have a history of fractures
• Have a history of osteoporosis or osteopenia

Here are some steps you can take to protect your bone health during weight loss.

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Exercise regularly

Exercise may be one of the best ways to protect your bones during weight loss. Weight-bearing exercise puts weight and pressure on your bones, which tells your body that it still needs to keep them strong.

Experts recommend combining strength training at least three times a week with at least 150 minutes of aerobic exercise each week.

Get enough protein, calcium, and vitamin D

Eating less during weight loss can make it harder to get all the nutrients your bones need. It’s important to pay attention to:

• Protein: Experts recommend getting more protein if you’re losing weight. You may need between 80 mg and 120 mg of protein each day.
• Calcium: Most adults should get about 1,000 mg to 1,300 mg each day.
• Vitamin D: Most adults need about 600 IU each day.

These are general guidelines, and your needs may be different depending on your overall health. Work with your healthcare team to determine how much protein, calcium, or vitamin D you need each day.

Monitor your bone health

Some people may need their bone health checked while losing weight. A dual-energy X-ray absorptiometry (DEXA) scan measures bone density and can help find bone loss before you have a fracture. Your healthcare team may recommend a DEXA scan every one to two years if you have a higher risk of osteopenia or osteoporosis. They may also track changes in your muscle mass, since losing muscle and bone can happen together.

Start treatment if you need it

If you already have osteoporosis or develop it during weight loss, exercise and nutrition may not be enough to keep your bones strong. Your healthcare team may recommend osteoporosis medication to help strengthen your bones and lower your risk of fractures. The right treatment depends on your bone density, fracture risk, and overall health.

Frequently asked questions

How is bone loss diagnosed?

A dual-energy X-ray absorptiometry (DEXA) scan measures your bone density and can show if you’ve lost bone. Your healthcare team will look at your results along with your medical history to understand your bone health. They may also order blood tests to check for low levels of important nutrients or signs that your bones are breaking down faster than normal.

Can you reverse bone loss?

You may be able to slow or stop bone loss, and even rebuild some bone. Your bone density may not return to the level it was when your bones were at their strongest. But even small improvements can help lower your risk of fractures. Treatment often includes a combination of medication, exercise, and good nutrition. Quitting smoking and limiting alcohol can also help protect your bones.

When should you see a doctor about signs of bone loss?

Talk with your healthcare team if you’ve had a fracture or are worried about your bone health. You should also ask about your bone health if you have a medical condition or take medication that can weaken your bones. Your healthcare team can order a bone density scan or blood tests to check for bone loss and decide if you need treatment.

Which weight loss medications are the worst for bone loss?

It’s not clear if one weight loss medication causes more bone loss than another. Researchers are still studying the differences between these medications. For now, the same steps to protect your bone health are recommended no matter which weight loss medication you take.

The bottom line

Some bone loss can happen when you lose a lot of weight, but that doesn’t mean weight loss is bad for your bones. These changes can happen whether you lose weight through surgery, lifestyle changes, or medications like Wegovy and Zepbound. Exercise and good nutrition can help protect your bones and muscles as your weight changes. Some people may also need bone density testing, especially if they already have a higher risk of weak bones. Your healthcare team can help you make bone health part of your weight loss plan.

This story was produced by GoodRx and reviewed and distributed by Stacker.