The purpose of this study is to compare the effects of different dose of whey protein intervention(in a daily dose of 0g, 10g, 20g) on lean body mass,body fat composition and muscular function state in the elderly with sacropenia.

Inclusion Criteria:

• People aged over 65 years.
• Usual gait speed less than 0.8m/s.
• Willing to participate in the study, consume the test product and perform all measurements.

Exclusion Criteria:

• nervous system disease.
• Other diseases with movement disorder such as stroke,fracture,arthritis.
• people who unconsciousness and can not complete questionnaire
• long-term regular use of protein and antioxidant.