Nutrition & Bone Health in Athletes: How Diet Prevents Injury & Builds Strength

When it comes to performance, most athletes focus on muscle, endurance, or speed. But bone health? It’s often overlooked—until an injury hits.

Stress fractures, delayed recovery, and long-term bone loss can derail even the most dedicated athletes. While training volume and biomechanics matter, nutrition plays a powerful role in keeping bones strong.

Why Bone Health Matters in Sport

Stress fractures are among the most common overuse injuries in sport, caused by repetitive loading—running, jumping, lifting—without enough time or nutrients for bones to recover and adapt. They’re painful, slow to heal, and can take athletes out of competition for weeks or months.

Looking long-term, bone health becomes even more critical. About 90% of peak bone mass is built by your early 20s, and most people hit their lifetime max by age 30. Athletes with lower bone density at this stage are more vulnerable to issues like osteopenia or osteoporosis later in life.

Key Nutrients for Bone Health

The basic nutrients that support bone health are the same for athletes as they are for the general population—but athletes may need more, due to the physical demands of training.

Important nutrients include:

• Calcium – Builds and maintains bone tissue

• Vitamin D – Regulates calcium absorption and bone metabolism

• Protein – Supports bone structure and repair

• Carbohydrates – Help reduce bone breakdown during and after exercise

• Fruits, vegetables, dairy, and fish – Provide a variety of bone-supporting vitamins and minerals

Athletes with dietary restrictions or food intolerances may fall short on some of these nutrients. In those cases, fortified foods or supplements can help—ideally under the guidance of a qualified nutrition professional.

Diet Related Risks to Athlete Bone Health

Energy Availability

One of the biggest bone health risks for athletes is low energy availability—not eating enough to cover energy needs for training, daily activities and basic body functions. This is a known issue in female athletes (as part of the Female Athlete Triad), but men may be affected too.

Research suggests that an energy availability below 30 kcal/kg of lean body mass per day can reduce bone formation, even if it doesn’t immediately increase bone loss. The effects are more pronounced with prolonged or repeated low energy states.

Low-Carbohydrate Diets

Low-carb diets, intentional or not, are common in recreational and elite athlete populations, but they may negatively affect bone metabolism, especially during periods of intense training. Even when total calorie intake is sufficient, inadequate carbohydrate can lead to increased bone resorption (breakdown).

Several studies suggest that consuming carbohydrates before, during, or after intense exercise can blunt the bone breakdown response, especially in endurance athletes. While more research is needed, the current evidence points toward including sufficient amounts of carbs everyday as a protective measure.

Protein Intake

Athletes often consume 2–3 times more protein than the general population. Earlier concerns suggested this could harm bones, based on the idea that extra animal protein intake increases acid load, pulling calcium from bones to buffer pH levels (the “acid-ash hypothesis”).

However, newer research shows that higher protein intakes may actually increase calcium absorption from food. When paired with adequate calcium intake, high-protein diets do not appear to harm bone health—and may even be beneficial for bone structure and repair.

Vitamin D Deficiency

Many athletes, especially those training indoors or during winter, have low levels of vitamin D. This matters because vitamin D helps regulate calcium and phosphorus levels in the body. Vitamin D deficiency can contribute to low bone mass and a higher risk of injury.

Keeping serum vitamin D levels above 50 nmol/L (20 ng/mL) is recommended to support musculoskeletal health, though the exact ideal range for athletes isn’t fully defined.

Calcium is a mineral that’s lost in sweat — and the longer or hotter the workout, the more calcium you can lose. During endurance or ultra-endurance exercise, especially in hot conditions, significant calcium loss through sweat can lower blood calcium levels. In response, the body may increase levels of parathyroid hormone (PTH), which pulls calcium from bones to bring blood levels back to normal. Over time, this process can increase bone breakdown.

It’s important to note that this concern applies primarily to athletes who are consistently training in these environments — not just a one-time session. Regular, repeated exposure to long-duration or high-heat training conditions is what puts athletes at greater risk for potential bone health impacts. Fortunately, smart dietary strategies can help reduce these effects.

Practical Takeaways

Research on nutrition and bone health in athletes is still evolving, but the current evidence supports these best practices:

• Start early:  Building strong bones begins in youth, with peak bone mass typically reached by around age 30. Prioritizing bone health during teenage and young adult years lays the foundation for lifelong skeletal strength.

• Monitor energy availability: Aim for at least 30 kcal per kilogram of lean body mass per day to maintain bone health.

• Balance macronutrients: Include enough carbohydrates to fuel training and help limit bone loss, especially during heavy training blocks.

• Eat enough protein — with calcium: High protein intakes should be paired with adequate calcium (800 mg/day or more) to support bone remodeling.

• Don’t overlook vitamin D: Regular screening and responsible supplementation may be needed, particularly for athletes training in low-sunlight environments.

• Consider calcium timing: Endurance athletes might benefit from a calcium-rich meal or supplement before long or intense sessions to help protect bone health.

Looking Ahead

Bone health isn’t just about staying healthy now —it’s about protecting your future. An athlete’s diet doesn’t need to be extreme, but it does need to be intentional. Training may push the body to its limits, and that includes the skeleton. Smart, consistent nutrition ensures bones can keep up.

Whether you're chasing medals, miles, or PRs, strong bones are non-negotiable. Start building the foundation today—through every meal, every rep, and every recovery window.