Going Lean

... requires resistance exercise and a healthy protein intake, especially as we age.

Lean muscle mass plays an important but often-overlooked role in our health , and it's never too soon to start taking care of it.

 

For a Good Cause

Each year between the ages of 30 and 60 the average person can expect to lose one-half a pound of muscle, a process known as sarcopenia.  At the same time, the average person will also gain one pound of fat.

As the years go by, this shift in body composition really adds up. At some point between the ages of 50 and 75, an average person may have lost some 25 percent of their lean muscle mass. 

Sarcopenia can affect our immune systems, our risk of injuries and our ability to recover from them. It can also play a role in chronic conditions like diabetes and osteoporosis.

As we age it's important to resist this physiological entropy by maintaining and building our reserves of lean muscle and fighting off the fat.

Reduce, Re-use, Recycle

 

Losing lean muscle can slow fat burning and muscle protein synthesis, therefore leading to further lean muscle loss. 

Lean muscle affects our metabolism in at least three ways:

 

Reduce 

Lean muscle is the largest location in the body where lipid oxidation, or fat burning, takes place.  Scientist think that less muscle can result in a diminished capacity to get rid of fat.

Re-use  

Muscle tissue is also the primary depository for glucose disposal. Once they fill to maximum capacity - around 250 grams of glucose for an average person - glucose then must be stored in the liver and in fat cells.  Exercise uses the glucose stored in muscles and in doing so helps to promote healthy glucose metabolism.  This is important in the preventing or minimizing chronic conditions like diabetes, macular degeneration, and perhaps even Alzheimer's.

Recycle

Recent research confirms that blood plasma levels of essential amino acids help to regulate protein synthesis. Low levels of these amino acids result in lower rates of muscle protein synthesis. What's more, the body needs amino acids for a number of important jobs in addition to muscle building. If there are not enough amino acids available in the blood,  it will break down lean muscle and use amino acids stored there for these other functions.

 

You Can Make a Difference

Scientists believe that our slowing metabolism and decreased ability to oxidize fat is a result of the typical decrease in lean body mass, rather than simply a function of age.

In order to prevent lean muscle mass as we age, experts recommend resistance exercise coupled with sufficient, quality protein intake. 

In fact, in his report for the U.S. Dairy Export Council on sarcopenia and whey protein, Dr. Paul J. Cribb states:

"An individual's habitual protein intake may prove to be one of the more important variables that influence the size of human muscle mass since recent work has confirmed that the concentration of EAA [essential amino acids] in the blood (plasma) regulate protein synthesis rates within muscle."