Findings published this month show that the right combination of healthy eating and physical activity may specifically strengthen the lumbar spine, or lower back, which is essential for spinal support, stability, and mobility.
“As people age, they naturally lose bone mineral density, increasing the risk of osteoporosis and fractures, particularly in the hip and spine,” says study coauthor Jesús Francisco García-Gavilán, PhD, a senior biostatistician at the University Rovira i Virgili in Tarragona, Spain.
“Fractures in older adults often lead to decreased mobility, a lower quality of life, and even heightened mortality,” Dr. Garía-Gavilán explains. “Maintaining bone health is essential for preserving independence and reducing the healthcare burden on aging populations.”
Why Bone Strength Is a Concern When Losing Weight
Despite all these benefits, weight loss in some cases can have a downside — negatively impacting bone strength.
“Weight loss can reduce the mechanical load on bones, leading to decreased stimulation for bone maintenance,” says study coauthor Jordi Salas-Salvadó, MD, a professor of nutrition at the University Rovira i Virgili. “Additionally, calorie reduction may result in nutrient deficiencies — for example, calcium, vitamin D, and protein — if not carefully managed, further contributing to bone deterioration. Hormonal changes and loss of muscle mass also play a significant role.”
The effects of weight loss on bone health are “nuanced,” according to Andrea Singer, MD, chief medical officer with the Bone Health and Osteoporosis Foundation, and chief of the division of women’s primary care at MedStar Georgetown University Hospital in Washington, DC.
“I think it’s hard to generalize,” says Dr. Singer, who was not involved in the research. “I discuss healthy weight with my patients in terms of cardiovascular risk, diabetes, and other diseases. If we need to recommend weight loss, there may be ways to at least mitigate some of the downsides, as this study shows.”
Diet and Exercise Makes a Difference When It Comes to Bone Health
In this analysis, researchers focused on a group of 924 adults, ages 55 to 75, who were overweight or obese. They were roughly evenly split between men and women.
Participants also had at least three of the characteristics of metabolic syndrome, a cluster of conditions that increase the risk of heart disease, stroke, and type 2 diabetes. These conditions include:
Patients were divided into two groups: One, the control group, had no specific physical activity recommendations and were instructed to follow a Mediterranean diet, which emphasizes plant-based foods and healthy fats, with no calorie restrictions.
In the intervention group, participants also followed a Mediterranean diet, but they had to reduce their normal calorie intake by 30 percent. They were also encouraged to meet standard exercise goals from the World Health Organization:
- 150 minutes per week of moderate-to-vigorous activity, specifically daily walking (45 minutes, six days per week)
- Strength, flexibility, and balance exercises three days per week
- 30- to 40-minute sessions of resistance training two days per week
The researchers measured the participants’ bone mineral density and bone mineral content at the beginning, middle, and end of the study.
After three years of follow-up, women in the intervention group had a 1.8 percent increase in lumbar spine (lower back) bone mineral density. They also had increased bone density in their femurs (thigh bones).
Women in the intervention group lost 2.5 percent of their body weight on average, compared with 0.9 percent loss for women in the control group. Men in the intervention group lost 3.4 percent of their body weight, compared with 0.5 percent in the control group.
Study authors saw no effect on overall bone health measures related to the diet and exercise interventions.
Still, they concluded that for older adults who are trying to lose weight, particularly women with obesity and metabolic syndrome, following a structured plan that combines a calorie-reduced Mediterranean diet, exercise, and behavioral support may help preserve or enhance bone density, especially in the lumbar spine.
Why Women Are More Prone to Weak Bones
Some of the factors that put women at higher risk of osteoporosis include smaller and lighter bones, longer life spans (since bone mass decreases over time), and menopause (which reduces bone-protecting hormones), Singer explains.
For all these reasons, women especially are encouraged to pay more attention to their bone health, she says.
“Osteoporosis is an under-recognized, underdiagnosed, and undertreated disease that can have significant consequences, mainly fractures, which lead to potential consequences and life-altering events,” says Singer. “If we’re looking at weight management, we need to think proactively about the things that we can do to maintain or improve bone health.”
How You Lose Weight Matters
“The combination of GLP-1 medications and exercise may help reduce some negative effects on bones,” says García-Gavilán. “Without exercise, these drugs can speed up bone loss, particularly in areas most prone to fractures, such as the hip and spine. Patients using GLP-1s for weight loss should include resistance and weight-bearing exercises and ensure they have adequate intake of calcium, vitamin D, and protein.”