Where the weight is retained would be important, old people normally lose muscle mass. Research from Medical College Georgia (Augusta U.) in 2017 explained the

Where the weight is retained would be important, old people normally lose muscle mass. Research from Medical College Georgia (Augusta U.) in 2017 explained the importance of tryptophan in the retention of muscle mass. Turkey meat and soy products are good sources. https://www.verywellhealth.com/tryptophan-7092730 https://www.verywellhealth.com/tryptophan-7092730