Bad to the Bones

Did you know that there are negative side effects of weight loss?  If you ask my husband, he’ll tell you that the constant need for new clothes is definitely a negative effect, but did you know that physiologically there are bad things that happen when we lose weight?  Studies have shown that as we lose weight, our bone density decreases.  Weight loss, in general, is a cause for earlier and more serious onset of osteoporosis, especially in women.  But, before you put that weight down and pick up a jelly-filled donut, let’s examine just why this occurs and what you can do about it!

Why, oh why?

There are two main reasons why bone density decreases as we lose weight.  The first reason has to do with physics.  When humans are overweight or obese, the bones respond by becoming stronger to handle the increased weight.  Up to a certain level, overweight individuals tend to have higher measurable bone density than those who are at a normal weight.  However, keep in mind that those who are underweight or are morbidly obese have the least amount of bone density. 

Recent studies have shown that increasing weight bearing activity does not help slow the reduction in bone density or,at best, it is minimal.  Increasing activity is definitely an important part of weight loss, but the skeletal benefits of activity actually begin to occur once an individual reaches a healthy weight and continues the activity. 

So, if the body naturally decreases bone density while we lose weight, why is it such a problem?  If the first reason bone density decreases is natural, what’s the second? The answer lies in the pastures…


That’s right! Milk.  Or more importantly, calcium.  A 2009 study showed that individuals who are attempting to lose weight by calorie restriction typically give up calcium rich foods first.  Furthermore, diets that suggest that followers restrict carbohydrates tend to lead participants to decrease foods that the bones need to stay healthy.  Foods such as milk, cheese and yogurt are often the first foods dieters eliminate due to their higher calorie and fat contents, but are the leading sources of calcium that the body needs!

What’s with Calcium?


Calcium is the most abundant mineral in the body.  The National Research Council shows that the average man has three pounds of calcium in their body, and the average female has two.  99% of the calcium found in the body is in the teeth and bones leaving 1% to the rest of the body.  But that 1% is where the danger lies.  Calcium is a major key to several body processes such as clotting, wound healing, blood pressure control, neurotransmission, digestion, energy and fat metabolism, muscle contraction, and connective tissue maintenance.  When your diet causes you to become low on calcium, the body systems have the ability to “borrow” what it needs from the teeth and bones, and this causes bone density to decrease at a higher rate. 

What can we do?

It seems like the obvious answer is to drink milk, right?  However, I have been surprised at the number of clients and individuals who have told me that they can’t stand milk.  Nutritional studies have shown that a high-calcium but low-fat diet actually help individuals lose weight faster!  But the key is to add low-fat calcium sources to your diet.  Skim or 1% milk, low-fat cheese, cottage cheese, and yogurts as well as green, leafy vegetables, broccoli, and cooked dried beans and peas are all wonderful sources of calcium that need to be a part of your diet. 

Recommended Daily Allowance of Calcium

Age Male Female Pregnant/ Lactating
Birth-6months 210 mg 210 mg  
7-12 months 270 mg 270 mg  
1-3 years 500 mg 500 mg  
4-8 years 800 mg 800 mg  
9-13 years 1,300 mg 1,300 mg  
14-18 years 1,300 mg 1,300 mg 1,300 mg
19-50 years 1,000 mg 1,000 mg 1,000 mg
50+ years 1,200 mg 1,200 mg  

Sources of Calcium

Food Milligrams (mg) per serving
Yogurt, plain, low-fat, 8 oz. 415
Cheddar Cheese, 1.5 oz 306
Milk, nonfat, 8 oz. 302
Milk, reduced fat (2%), 8 oz 297
Milk, whole, 8 oz 291
Yogurt, fruit, low fat, 8 oz 245-384
Calcium fortified orange juice, 6 oz 200-260
Tofu, soft 1/2 cup 138
Calcium fortified cereal 100-1000
Soy beverage, calcium fortified, 8 oz. 80-500

What about supplements?

If you were like me, you look at that chart and think that there is no way that you can eat enough food to get your calcium needs and still lose weight, right?  That’s where calcium supplements come into play.  There are two main forms of calcium in supplements – carbonate and citrate.  Calcium carbonate is more abundant and is rather inexpensive.  Citrate is more expensive, but is absorbed more easily by those with reduced levels of stomach acid.   But the difference in absorption between carbonate and citrate can be leveled if calcium carbonate is taken with food.

But keep in mind, the body can only effectively absorb calcium in increments of 500mg or less.  So if you take a 1000mg supplement, can you guess where over half of that supplement will end up?


That’s right.  The FDA recommends that individuals break up their calcium supplements and take a 500 mg supplement twice a day to get an adequate amount.  However, they also recommend that at least 30% of your calcium come in the form that the body can best use – food!  Why is this?  Because there’s another pesky partner in this battle for weight loss and bone density – Vitamin D!  The body needs Vitamin D to help utilize the calcium and most foods rich in calcium are also, conveniently, rich in Vitamin D.  So don’t eliminate dietary calcium and replace it with a pill.  Your body will thank you!


Now that you know that there is a potential negative side effect to weight loss, I hope you will take the steps to prevent it from occurring.  Keeping your calcium levels at an adequate level while losing weight will help minimize the decrease in bone density, helping reduce the possibility of osteoporosis, stress fractures, muscle cramping, and hip and spine fractures.  Small dietary changes today can ensure that you are able to stay….

moving 4 life!


~ by Shawna on April 6, 2010.

2 Responses to “Bad to the Bones”

  1. This is why I love Body for Life. Bill encourages lots of dairy intake, especially at night and as a source of protein. Once my thyroid’s working properly (SOON!), I think I’ll move back in the BFL direction. Thanks for the encouragement!

    • I was so glad to see good news today from you on FB! I’ve seen some great results from BFL – I think any diet that promotes a healthy, well-rounded diet is a great tool to use! BFL doesn’t seem so punishing as others that require you to “give up” everything you enjoy! Good luck! Keep me updated on how you’re doing!

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