Honestly, in the US, at least, we've run into the opposite problem - we eat too much meat for a healthy diet (on average, at least).

Suffering from success.

It's bad etymology unfortunately. One referred to time and the other to grinding. The closest I got is that a luncheon was original a chunk of a food item. Nuncheon was a "noon-drink" which makes sense when you consider that many workers would consume alcohol as their primary lunchtime calories during certain parts of history.

It's entirely possible that such diseases are more prominent in modern environments.

I guess it's also possible that such people may have just died in childhood instead.

There are lots of gluten-free options. Oats, sorghum, barley. It's not all wheat.

You need one existential crisis step further. With very rare exception (some life we've found living near thermal vents in the deep sea) all calories are derived from the sun through photosynthesis. I suppose you can muddy the waters with man made light sources powered by non-solar energy, but with the rare exception of nuclear power (or tidal, since that's moon's gravity, or geothermal, and a few other niche sources, but even out together these make up such small percentages), most man made energy is just harvesting the sun's energy with more steps. Oil, that's just ancient plant matter. Wind, that's just air currents which only exist due to heat energy from the sun. Solar, lol. Not that grow lights even make up enough to matter, but it's a fun part of the existential equation.

We eat the sun.

Just salt me and call it a day; I'm ready for the next stage of human diet

Mushrooms are fucking gross dude. Imo instant dish ruiner.

The Greek philosopher Epicurus, who posited that the path to human happiness was (sustainable, appreciated) pleasure, once supposedly impressed a ruler so much that the ruler offered him vast estates, should he wish it, as a reward for his wisdom.

Epicurus just asked for some bread and a bowl of hot cheese, so he could "feast like a king".

Gotta appreciate the good things in life!