I would like to know if it is safe to drink a protein shake once a day when I don't work out. I may have to walk a lot and I just have one meal a day, according to Tim Hortons some time. So I was thinking if I could have a protein shake once a day...as I'm having both weight and a lot of hair loss due improper diet recently. Also could you suggest which shakes out there in the market should I look for?
Sure you can drink a protein shake even if you're not working out in a classical sense — like doing some heavy "macho-stuff" at a gym or something — but walking definitely counts as "physical fitness" type of exercise too.
Proteins are just basic building blocks our body needs for normal functioning, and most certainly not just for the "reconstruction" of muscle tissue after intense workouts, so if you ask me, you'd probably do well to include them in your diet, especially if you've recently been on some low-protein diet regime (but like somebody already commented, you should consult a nutritionist if you want to be 100% sure).
And while I certainly won't state any brands here, my advice would be to check out the nutrition labels and Google any unfamiliar ingredients (to rule out any harmful ones), but other than that, drinking protein shakes really isn't really all that different from eating a steak or something.
If you are having only one meal a day and if you really want to use protein powders instead of healthy natural foods, then you definitely need to choose egg white powder protein because it will be digested slowly, releasing a steady level of essential aminoacids during hours into your blood. Casein protein powders are the second best option, they are still slow digestion protein, but not even as a slow digestion protein as white eggs.
You want to avoid whey protein because it will be diggested faster, giving you a quick excess of aminoacids that will be wasted, because your body has little ability of storing them.
In any case, having a single meal a day is unhealthy and you should try to avoid it.
Here is some reference regarding the different absorption rates of proteins. According to a study quoted there, aminoacids from egg white protein are absorbed at a rate of ~1.4 g/h, casein at ~6 g/h and whey at ~9 g/h. You don't find many references like that, because of the powerful marketing of the supplements companies, who are interested in selling you casein as the standard of "slow" protein instead of egg whites (easily found everywhere).
Protein shakes are fine to drink without working out but this probably will not contribute to any muscle building if that is what you are looking for. It will probably add to your body weight in general. If you do work out, it is a different story where the protein will greatly contribute to your muscle building which of course will depend on how much stress you place on the muscle itself. Look for a book called "home workout bible" about this subject, it is great and cheap.
I can't say what is and isn't safe for you. You should see a nutritionist.
However, in general it is safe to consume protein powder.
If you believe you are not consuming enough protein, than that is exactly what the protein powder is for.
Most people that feel they need the extra powder require more protein because they are working out frequently, but that doesn't mean you can't use it too.
Note: I am not saying a protein powder will give you all of the nutrients you need or that it will solve your problems.