Caloric restriction causes bone loss. It's the conclusion of a study that compared the impacts of weight loss by caloric restriction to weight loss by exercise. The implications of this finding are of critical importance to anyone who hopes to improve bone health and avoid fractures while losing weight.
Whether you're not eating a full and varied diet because of a weight loss plan or due to self-isolation during the COVID-19 pandemic, the result could be detrimental for your bones.
Today we'll look at the details of this study, the power of exercise to achieve both weight loss and optimal bone health, and the importance of proper nutrition for staying healthy, strong, and fit.
The Effect Of Caloric Restriction On Bone
Researchers at The Washington University School of Medicine followed 48 adults over the course of a year to study the impacts of caloric restriction-induced weight loss and exercise-induced weight loss on bone quality.
They randomized the participants into three groups: a calorie-restricted (CR) group, a regular exercise (EX) group, and a healthy lifestyle control group that was not attempting to induce weight loss. Researchers looked at the change in hip and spine bone mineral density, as well as bone markers and hormones to assess bone health.
The caloric restriction group and the exercise group saw the same reduction in body weight — both were effective for weight loss — but the caloric restriction group lost bone mass in their hips and spine, while the exercise group didn't lose any bone mass. Both groups saw increased bone turnover.1
This was the researchers' conclusion:
“CR-induced weight loss, but not EX-induced weight loss, is associated with reductions in BMD at clinically important sites of fracture. These data suggest that EX should be an important component of a weight loss program to offset adverse effects of CR on bone.”1
Diet is essential to good health, and following a pH-balanced diet is a very healthy way to avoid weight gain. Many foods that are high in calories are automatically restricted, and the calories you eat are accompanied by bone-building vitamins and minerals.
When it comes to weight loss, the study above makes clear that restricting calories leads to bone loss, ultimately making you less healthy. Fortunately, exercise provides an effective alternative that is not only safe but also compatible with the pH-balanced diet for both weight loss and building stronger bones.
A study found that caloric restriction-induced weight loss is associated with bone loss, while exercise-induced weight loss is not. Caloric-restriction reduces bone-quality, which increases the risk of a fracture.
Exercise-Induced Weight Loss Targets Abdominal Fat
Not only is exercise a bone-safe way to lose weight, but the specific type of weight-loss triggered by exercise has bone-health benefits.
Research conducted at Nanyang Technological University in Singapore evaluated the fat-free mass (FFM), fat mass, and percent body fat of thirty obese men before and after four months of regimented training in the Singapore Armed Forces.
The men lost an average of 26 pounds, which was attributed to a reduction in fat mass. The participants' waist circumference and hip circumference both decreased, but the waist reduction was nearly twice as substantial as the hip reduction. The majority of their weight loss was from abdominal fat.2
Here's a direct quotation from the conclusion of the study:
“Large exercise-induced weight loss is associated with a preferential reduction in abdominal fat and corresponding maintenance of FFM. Such an effect on body composition should reduce disease risk and the eventual weight regain that typically follows diet-induced weight losses with obese subjects.”2
This is particularly important for Savers since excess abdominal fat is associated with reduced bone mineral density.
Another study of obese men and women found that the presence of visceral fat — the fat located between organs in the abdominal cavity — was positively associated with reduced bone mineral density and reduced bone integrity. The more belly fat a participant had, the more likely they were to have weaker bones than their peers with leaner mass.3
Taken together, these studies locate a bone-health benefit of exercise-induced weight loss.
A study of military recruits in training found that exercise-induced weight loss created a preferential reduction in abdominal fat. Another study determined that abdominal fat is associated with low bone mineral density and reduced bone integrity. Exercise-induced weight loss preferentially burns body fat that is associated with poor bone health.
Exercise Recommendations For Weight Loss
According to the American College of Sports Medicine, for most people, there is a range of weekly exercise time that achieves weight loss, and that prevents weight gain. If you're hoping to lose weight, these recommendations can help you accomplish that goal using bone-building exercise.4
- 150 to 250 minutes of moderate-intensity physical activity per week generates modest weight loss.
- 250 minutes or more of moderate to vigorous activity per week generates more substantial weight loss.
- About 150 to 250 minutes of moderate-intensity exercise prevents regaining weight.
You can divide up those minutes in a way that works for you. Here are some suggestions on how to divide 210 minutes of weekly workout time:
- Even split, every day: 30 minutes a day seven days a week
- Even split, one or two days off: 35 minutes six days a week or 42 minutes 5 days a week
- Heavy days and light days: two 60-minute workouts and two 45-minute workouts a week
- Limited long workouts: three 70 minute workouts a week
- Evenly spread multi-workout days: two 15-minute workouts (for example, morning and evening) 7 days a week.
- Condensed multi-workout days: two days with two 45-minute workouts each day, and one day with one 30-minute workout.
Of course, there are many more ways to divide up your minute-per-week exercise goal, whatever it may be. But you’ll probably feel inclined toward one of the above examples, based on your weekly schedule and personal preferences. Follow that impulse, and build a plan that is appealing to you.
The American College of Sports Medicine recommends 150-250 minutes of moderate to intense physical activity per week for weight loss. For substantial weight loss, more than 250 minutes is recommended, and 150-250 minutes are required to prevent regaining weight.
What This Means To You
Weight loss is fully compatible with building stronger bones. During self-isolation because of the novel coronavirus, it's important to provide your body and your bones with the robust diet and regular exercise they need to flourish.
If the quantity of exercise required to lose weight sounds overwhelming, take advantage of the support and guidance of SaveTrainer. SaveTrainer is The Save Institute's one-stop solution for all of your workout needs. From video workout classes with licensed trainers to customized workout plans to keep you on track, SaveTrainer has everything you need to succeed.
The Save Institute has always rejected the incorrect notion that restriction leads to growth. Starving yourself won't make you healthier, so stock your pantry with bone-building foods, enjoy eating healthy meals, and keep your body active every day!