Maybe we should, maybe we shouldn't but the studies for sugar and minimum wage spread wide enough that it's easy to see these convenient conflict-of-interests everywhere.
In many cases it results in consumer confusion and serious health issues (sugar vs saturated fat war you noted).
- because they are perhaps not very bright, maybe mentally-disabled (Downs syndrome people for instance), possibly just naturally very slow, inexperienced, very young, very old, physically feeble or otherwise considered to be unlikely to be productive would-be employees who
- are then legally prevented from getting a job unless of course the state wishes to force employers not to hire the most productive staff to be paid the minimum wage. And that's not going to happen in a free society and nor should it. Everyone has their value. But don't let's pretend that value (for a specific job) is the same for all of us.
If we chose to follow that rule we would end up with very few studies in economics, and the world would be poorer for it.