The evolutionary pattern was created because food was unreliable and energy demands were unpredictable - but high, due to the large brain. (Possibly larger than it is today, but there seems to be conflicting data there.)
Now, rationing extreme energy foods is certainly one option, but it's not a particularly satisfactory one as the energy demands vary by profession and by time within a profession. You simply can't predict what people will need and there's no way to standardise this.
There is a second option. Intense focus is impossible for beyond about 45-90 minutes at a stretch, or for more than 3-5 hours in a day. Meetings degrade intelligence, according to psychological research, so you want to minimise those. After about 7 hours, work will mostly have negative value. If you increase the amount of high physical activity for at least an hour a day (and potentially longer if the amount of soft work is minimal in the job) then you will improve physical fitness and general health, without having to substantially alter diet. However, that still only gets you so far, because a poor diet still impacts physical and mental health, and can lead to brain decline. (It's a big factor in poor brain health in children in schools.)
A third option, then, is to actually improve meal quality in schools and for workplaces to work with the food industry to provide cheaper/easier access to high quality foods that actually taste good, not merely sensible energy foods. This would seem to be target solution, with in-work exercise to supplement it.