So biochemistry is more of the very small-scale chemistry of biology (cellular and molecular) of humans, plants and other organisms but has some cross-over with biomedical science whereas biomed is more on a larger scale, looking at disease, physiology etc. more human-focused but still with some cross over with biochem. Biochem is definitely more broad. If you love molecular biology, cycles etc. you will enjoy biochem but if you enjoy more medical stuff but not full-on medicine biomed would be for you. Sorry it makes sense in my brain LOL. I would recommend you compare the course structures on uni websites.