Why did my midwife tell me to cut out certain foods...after 32 weeks?

My midwife told me to cut out red meat/sugar/dairy after 32 weeks, something about hormones in the blood and not making the birth harder. 
Does anybody know what scientific base there is for this (if any)? I get most of my calcium from yogurt and I eat red meat pretty regularly. Sugar shouldn't be too terrible as I'm not a big sweets person. But I don't necessarily want to cut out my yogurt and red meat if this isn't a thing. 
Or is it a thing and I'm just ignorant?