If you think junk food goes directly onto your hips, you're right. But it gets worse. It gets into your hips, and into other bones in the body, too.
Food that is high in fat and sugar robs the skeleton of the building blocks it needs to grow and remain strong to ward off degenerative conditions like osteoporosis.
There are two mechanisms for this bone robbery.
First, a diet high in saturated fats and sugar blocks ingested calcium from being absorbed, so it excretes in the urine. Thus, the calcium needed for healthy bones washes through the body and is lost.
Second, saturated fats tend to form insoluble 'soaps,' which coat the intestines. This coating becomes a barrier to the calcium bones need. Thus, the calcium from the cheese on a burger will pass through the intestines mainly unused.
The picture is not pretty. Junk food layers fat onto a skeleton that it weakens of the ability to support the extra weight.
Approximately two million Canadians suffer from osteoporosis, a disease known as the 'silent thief' because, with no symptoms, it robs the bone of tissue leaving it with thousands of tiny pores. Porous bones can break with little stress.
Women are particularly at risk, with a rate of osteoporosis twice that of men. One in four women in Canada over 50 has osteoporosis. One in three women over 65 will suffer a hip fracture. About 20 per cent of hip fractures related to osteoporosis will result in death.
Treating osteoporosis and related fractures costs Canada's public health system an estimated $1.9 billion per year.
Your diet can be an enemy or an ally in your battle against osteoporosis.
A growing child, near puberty and rapidly laying down new bone, could optimize his or her bone growth and accumulation by eating healthy foods and being physically active. The more bone developed, the lower the chance of fractures from osteoporosis later in life. Parents and grandparents, however, are past the stage of building bone. By following a healthy diet, being physically active and, if necessary, taking medication to slow bone loss, they can reduce their likelihood of fractures from osteoporosis.
A healthy diet is balanced and includes a variety of foods -- vegetables, fruits and whole grains -- and foods low in saturated fats, salt and sugar.
Maintaining a healthy diet, however, is not just about knowing which foods to select. It's also about managing the environment that influences food choices. In this area, we have options.
We can strictly limit the transfat levels in food products and ban, as California has, transfats in restaurants. Or we can require, as New York City has, that calorie counts be posted on menu boards in the same font size as price. We could also eliminate unhealthy foods in vending machines and at cafeterias in schools, recreational centres and hospitals.
Baby boomers were the first generation to grow up on fast food, and they have created a dietary legacy of high fat and sugar. Today, 1,600,000 Canadian children are obese or overweight -- more than one of every four children.
Boomers themselves have reached the stage in life when they are most susceptible to bone and joint disorders.
But while concerns have been expressed about early onset of cardiovascular illness and diabetes from a high fat and sugar diet, scant attention has been paid to the exposure of millions of people to significantly increased risk of osteoporosis, premature joint wear and other skeletal conditions that can silently rob them of their health.
We can turn the tide, but we need to put measures in place now to protect our bones and in the process, improve our overall health.
Cy Frank is an expert adviser with EvidenceNetwork.ca, and the executive director of the Alberta Bone and Joint Health Institute. Ron Zernicke, a kinesiology professor at the University of Michigan, co-authored this piece.