A new review examines how extra body weight and weight loss affect your bones. Researchers found that people with obesity actually have denser bones, which sounds good, but they may break their ankles and lower legs more easily. When people lose weight, their bones become less dense and may break more easily, especially at the hip and wrist. The good news is that exercise, vitamin D, calcium, and protein can help protect your bones during weight loss. New weight loss medications might also help keep bones stronger while you’re losing weight.
The Quick Take
- What they studied: How obesity and weight loss affect bone strength and fracture risk
- Who participated: This was a review of existing research, not a new study with participants. Researchers looked at many previous studies about obesity, weight loss, and bone health.
- Key finding: Extra body weight makes bones denser, but weight loss—especially from surgery—reduces bone density and increases fracture risk. However, exercise and proper nutrition can help protect bones during weight loss.
- What it means for you: If you’re losing weight, you should focus on exercise, getting enough calcium and vitamin D, and eating enough protein to help keep your bones strong. Talk to your doctor about the best approach for your situation.
The Research Details
This is a narrative review, which means researchers read and summarized many existing studies about obesity, weight loss, and bone health. They didn’t conduct a new experiment with participants. Instead, they looked at what other scientists have discovered and organized the information to show patterns and connections.
The researchers examined studies about how extra body weight affects bones, what happens to bones when people lose weight through diet and exercise, and what happens after weight loss surgery. They also looked at studies about medications, supplements, and exercise that might help protect bones.
This type of review is helpful because it brings together information from many different studies to give a complete picture of the topic. However, it’s based on other people’s research rather than new data collected specifically for this review.
Understanding how weight and weight loss affect bones is important because doctors need to help people lose weight safely without damaging their bones. This review helps doctors understand the risks and benefits so they can give better advice to patients.
This is a narrative review, which means it’s based on the authors’ selection and interpretation of existing research. It’s not as rigorous as a systematic review that uses strict rules to select studies. The findings are reliable for understanding general patterns, but individual results may vary. The review was published in a respected medical journal, which suggests it was reviewed by experts before publication.
What the Results Show
The review found that people with obesity have higher bone mineral density, which means their bones are denser. This might seem like a good thing, but it doesn’t always mean stronger bones. People with obesity actually have a higher risk of breaking their ankles and lower legs, even though their bones are denser.
When people lose weight, their bones become less dense. This happens because weight loss increases the rate at which the body breaks down bone. The loss of bone density is especially noticeable in the outer layer of bones (called cortical bone). This reduced density increases the risk of fractures, particularly at the hip and wrist.
Weight loss from surgery (bariatric surgery) causes more bone loss than weight loss from diet and exercise alone. This is because surgery causes more dramatic changes in the body, including hormonal changes and nutrient absorption problems.
The review identified several reasons why weight loss affects bones: less weight puts less stress on bones (which makes them weaker), people often lose muscle along with fat (and muscles help support bones), hormones change during weight loss, and people may not get enough calcium, vitamin D, and protein.
The review found that new anti-obesity medications (like GLP-1 agonists) may help protect bones better than older weight loss methods. These medications might reduce bone loss while still helping people lose weight. The review also confirmed that regular exercise, vitamin D supplements, adequate calcium intake, and enough protein can all help reduce bone loss during weight loss.
This review confirms what previous research has shown: obesity protects against some types of fractures (hip and wrist) but increases risk for others (ankle and lower leg). The new information is about emerging medications that might help protect bones during weight loss, which is an important development because previous weight loss methods often harmed bone health.
This is a narrative review based on the authors’ selection of studies, so it may not include all available research. Different studies may have used different methods, making it hard to compare results. The review doesn’t provide specific numbers about how much bone loss occurs or how much fracture risk increases. Individual results vary greatly depending on age, sex, how much weight is lost, and other health factors.
The Bottom Line
If you’re losing weight, take these steps to protect your bones: (1) Exercise regularly, especially weight-bearing exercises like walking or strength training (high confidence); (2) Get enough calcium through food or supplements—aim for 1,000-1,200 mg per day depending on age (high confidence); (3) Ensure adequate vitamin D, either through sunlight, food, or supplements (high confidence); (4) Eat enough protein to maintain muscle mass—aim for 0.8-1.0 grams per pound of body weight (moderate to high confidence); (5) Talk to your doctor about your specific situation, especially if you’re considering weight loss surgery (high confidence).
This information is important for people with obesity who are considering weight loss, especially those thinking about weight loss surgery. It’s also relevant for doctors and healthcare providers managing weight loss. People with osteoporosis or a family history of fractures should be especially careful. Older adults and women after menopause should pay extra attention because they’re already at higher risk for bone loss.
Bone loss can begin within weeks of starting weight loss, but significant changes usually take several months. The good news is that protective measures like exercise and proper nutrition can start working immediately. If you’re losing weight, you should have your bone health checked before starting and periodically during weight loss, especially if you’re losing a large amount of weight or having surgery.
Want to Apply This Research?
- Track daily calcium intake (target: 1,000-1,200 mg), vitamin D intake, minutes of weight-bearing exercise, and grams of protein consumed. Monitor these weekly to ensure you’re meeting targets while losing weight.
- Set a daily reminder to take a vitamin D supplement, log one weight-bearing exercise session daily (walking, dancing, or strength training), and include a protein source at each meal. Use the app to log calcium-rich foods and track progress toward daily targets.
- Create a monthly check-in to review bone health metrics: exercise consistency, nutrient intake averages, and weight loss progress. Set alerts for annual bone density screening appointments if recommended by your doctor. Track any new aches, pains, or concerns about bone health to discuss with your healthcare provider.
This review summarizes existing research about how obesity and weight loss affect bone health. It is not a substitute for professional medical advice. Before starting any weight loss program, especially weight loss surgery, talk to your doctor about your individual risk factors and how to protect your bone health. Your doctor can recommend the best approach based on your age, sex, current health, and medical history. If you have a history of fractures, osteoporosis, or other bone conditions, inform your healthcare provider before making changes to your diet or exercise routine.