As said above, the limit on feed rate is usually based on the machine or the tool. If the cutter has a nearly vertical face to the side that is feeding into the cut, too high a feed rate will cause it to bear on the face of the work and just push, which will push the toolpost, break the cutter, or bind up the feed on the lathe. Adding clearance to that leading face allows a higher feed rate, but also takes support from under the edge of the cutter, so there is a give and take where you gain feed, but lose strength to where the huge bite you are taking finally breaks the edge of the cutter off. This is more applicable to a hand ground HSS tool where you can put as much clearance on it as you desire.
On low strength materials like aluminum and cast iron, you can run pretty insane feed rates for roughing, just to put chips on the ground and get on with the job. On high strength alloys, tough materials and interrupted cuts, that lack of support is going to result in a broken tool.
Within reason, set your speed to the proper sfm for the cutter and material and start a cut at whatever depth of cut you desire. If the chip is stringy, up the feed rate until it breaks clean into tight 9s or the tool starts pushing the post or you fear breaking the cutter or feed on the lathe. If you are concerned about the load, drop the feed while hand feeding and see how hard it is to feed the tool by hand at that rate. If it is REALLY hard to feed, back up and punt. If you just can't get it to break, drop the speed a little and see if the chips curl more. Some materials just WILL NOT break (some stainless alloys like 304), other material like cast, ductile iron or bronze can't help but break. In those cases, just jack the feed up until it gets scary.
Lastly, some machines do better with HSS than carbide... lighter lathes, especially. The little Jet at the hydraulic shop couldn't run a carbide cutter to save its life. You could get these little scratch cuts at 300rpm, .030 depth and .005 feed and just pray it didn't start chattering. I got a stick of HSS, ground a high rake hook tool with pretty generous front clearance and set it to about 100rpm in backgear, but went to .100 on the depth of cut and jacked the feed rate to .015/rev. The foreman walked by and did a double take. It wasn't running very fast, but it was flat laying metal in the pan. Tripling depth of cut and tripling the feed rate resulted in a faster metal removal rate than the carbide could provide because carbide couldn't take that kind of shearing grind on the edge without chipping. I had dropped the speed by a factor of three, but upped the depth of cut my three, so that was a wash. Upping the feed rate made it work three times faster.