But in an era of widespread suspicion that Big Government is reaching too far into Americans’ private lives (recall the deep controversy over the Affordable Care Act’s mandate for everyone to buy health insurance even if they didn’t want it), that is very much a current source of worry, at least in some sectors — and particularly among some conservative constitutional scholars.

At the Food and Drug Administration this week, in the kind of announcement that stirs up such worries, it told the nation about how the government will be reaching into the nation’s restaurant chains to dictate what they say about the weight-affecting contents of their regular menu items (Thanksgiving turkey, apparently, will be exempted as a seasonal item, as also will plum pudding with brandy at Christmas time).

The announcement, though, came with hardly any justification of its constitutional authority to do that.   The FDA clearly operates on the assumption that it has authority from Congress to do what it is doing, and thus silently assumes that it must be acceptable under the Constitution’s Commerce Clause.  The agency noted that it has had authority from Congress since 1990 to require nutrition labels on food, and that the Affordable Care Act extended that authority to restaurant menus and vending machines.