This project evaluates the use of different types of proteins from various food sources after an exercise session, on muscle mass and physical capacity in aged sarcopenic men (who have low muscle mass). Specifically, researchers want to:

• Examine the efficiency of protein intake after exercise on muscle mass and physical abilities;
• Examine the impact of exercise and proteins on blood lipids (LDL cholesterol, HDL cholesterol, total cholesterol and triglycerides);
• Examine the impact of exercise and proteins on liver enzymes;
• Examine the impact of exercise and proteins on a hormone that controls hunger;
• Evaluate the program's impact on the ability of the body to produce energy.

All participants are exercising (resistance training) and ingest one of the 3 different sources of proteins, immediately after training:

• Milk proteins (from milk beverage)
• Essential amino acids (added to a soya beverage)
• No protein (rice beverage - control group)

Our hypothesis is that proteins from milk will induce a gain in muscle mass and physical function equivalent to the essential amino acids (EAA). We anticipate that both milk proteins and EAA will be both superior to control group.

This would represent an interesting finding since milk is more accessible, palatable and cheaper than essential amino acids commercial mix.

Inclusion Criteria:

• 65-75 years
• francophone or understanding French
• muscle mass index < 10.75 kg/m2 (Janssen et al, 2004)
• body mass index <30kg/m²
• weight stable (< 2 kg) for 6 mo
• no resistance exercise for 3 years
• controlled blood pressure for at least 6 months

Exclusion Criteria:

• major physical disability
• medical treatment influencing metabolism
• statin treatment
• diagnosis or any sign of kidney disease