How do you prevent bone loss when losing weight at an older age?

Losing weight at an older age almost always comes with some degree of bone and muscle loss. People who simply eat less lose, on average, 5% of their muscle mass and 3% of their hip bone density over the course of a year. That may sound modest, but muscle loss and bone loss reinforce each other: less muscle means less mechanical load on the bone, which raises fracture risk even further.

Strength training is the most effective countermeasure. People who combine resistance training with their diet retain significantly more bone and muscle. In studies, bone loss in the hip fell from 3% to around 0.5 to 1%. Strength training also works in a site-specific way: the bones you load during training benefit the most. Adding aerobic exercise on top of that further improves overall endurance and physical functioning.

Eating enough protein amplifies the effect of strength training. Without sufficient building blocks for the muscles, strength training delivers less benefit. Although exact gram-per-day figures were not reported in the available studies, a high-protein diet is consistently recommended as part of any weight-loss strategy in older age.

Creatine (as monohydrate) is an additional option that, when combined with strength training, shows positive effects on muscle and bone health. This is based on a review study, not a large randomised trial, so the level of certainty is moderate and it is not a substitute for exercise and nutrition.

Popular weight-loss medications based on GLP-1 (such as semaglutide) and bariatric surgery deserve extra attention. With this type of weight loss, more than a quarter of the weight lost consists of lean mass, meaning muscle and bone. That is a real risk of sarcopenic obesity: you become slimmer but weaker. Anyone losing weight at an older age with such a medication or procedure would do well to discuss this actively with their treating physician and to combine it with strength training at the same time.