Scientific research shows that eating protein foods is important in avoiding the disaster of having a fall in later age (see the original paper here) and also that protein from animal sources like meat, eggs and dairy might have an advantage in building and maintaining muscle in those years (one paper on that is here).
There's no question that it gets harder to build and to keep your muscles strong as you get older, but there is no alternative to doing just that if you want to continue to enjoy a productive and independent life. You need to do a combination of activities that involve balance, strength and aerobic components: things that have you shifting your weight onto different feet to challenge you; lifting, pushing or pulling weights; and puffing a bit.
There are lots of good exercise programs available now - just check anything new with your doctor first to be sure it will suit you. Here is one to give you some ideas - it's from the USA and I've chosen it because it gives a lot of information as well as specific guidance on exercises to do. But ask around at your local health centre and your doctor's - there are great classes starting up everywhere.
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