Fame
Unless you decide to become one of those disreputable TV nutritionists who starts their own scammy diet craze, you're probably not going to find much fame in this field. Not to mention that if you did that, you wouldn't really still be a food scientist.
Even folks like the head of the FDA (Michael Taylor, ever heard of him? Didn't think so.) don't tend to be household names. While your research, products you develop, or food-related projects or movements you take part in or even lead might gain some clout, you, yourself, are most likely going to be doomed to anonymity.
If you're in this field to get popular, you don't really have your head on straight anyway—of course, you could always shoot for a show on the Food network. Folks who enter this field get their satisfaction from the work itself, not the fame they receive as a result. If you produce some really hard-hitting results, you might earn yourself a write-up in the paper, or some food magazine, or even some sort of award. But the buzz that lasts won't exactly be fame—no, there's a better word for it…clickbait.