I add protein powder to my fruit/probiotic shake in the morning. I don't go for any of those pre-mixed things because they usually contain a lot of sugar and some of them contain a lot of sodium but I can't eat first thing in the morning so I start with a shake and then mid-morning I have steel cut oats with berries or eggs or something (my shake consists of: unsweetened almond milk or coconut water, liquid probiotic and/or plain greek yogurt, fresh fruit and a scoop of whey protein powder and sometimes a little fresh ginger). I just can't do solid foods first thing in the AM. I think it helps keep me feeling full but I don't know about the speeding up of the metabolism or anything. I just do it beause I can't put solid food in my body until I have been up for a few hours (been that way since I was kid). I don't know if that helps ... but good luck on your journey!!
Protein is good for weight loss in general. It doesn't matter what form it's in. As always, check the nutrition label and see what else goes with it. You wouldn't think a chicken coated with brown sugar is good for weight loss so don't think a protein drink loaded with sugar is good for weight loss.
I'm doubtful that they speed up your metabolism, because the only metabolic activity from eating is chewing. There might be a slight thermal effect, but don't expect anything more than 20 cal/day that you can add to your daily burn.
I've found that protein snacks are more effective for killing my appetite than other snacks, and they help keep my calorie consumption down. I like them mid-morning or mid-afternoon, usually a bar or a can of fish, to hold me over for 2-3 hours.
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