Biochemistry would be the best imo. Biology, chemistry or even nutrition will also be very beneficial as you have to take upper division science courses to complete the degree which have many applications for medical school/ pharmacy school. I understood the concepts from my prereqs much better after taking the upperdivision courses.
I agree. Being a Biochem major, I can tell you that if you have a good biochem dept. at your school, then you'll most likely have very enthusiastic professors teaching those classes, which will make those classes even more interesting. Biochemistry is the study of physical and chemical properties of the macromolecules that make up all living organisms. You get more detail about proteins, nucleic acids, carbohydrates, and lipids than you would if you do a bio or chem degree. I believe it's more beneficial in pharm school than bio and chem on this point.
But, more than that, biochem degree is a lot more marketable than a bio degree. At UH, there are around 1,000 or more bio degrees each year, versus about 100 biochem degrees. There might be more or less for chem degrees, I'm not sure (I only know 1 chem major lol). In Houston, the job market for bio degrees is saturated, making it harder for recent bio grads to get jobs; plus, if a bio grad got a job, the pay rate would be significantly lower due to higher competition [i.e. They can fire BioGrad A and get a new BioGrad, B, for cheaper]. Biochem degrees, on contrast, have a bit more specificity, but the pay rate is higher and the jobs are a lot more interesting than just a bio degree can handle.
Honestly, it all comes down to how your school's Bio and Biochem departments are.