You are working, as in earning money. Therefore snacks are an option. Six months down the line this guy is going to be looking back and seeing snacks as part of the good-old-days, when he had money for such things.

My advice would be to pare food down to the basics, as in a sensible lunch and a proper, cooked from fresh evening meal with no snacks. Get the sacks of pasta and rice in with canned goods, e.g. tomatoes, in bulk. Then do the rest of the shopping by bicycle, i.e. the vegetable shopping. Give up meat and go veggie on cost grounds. The jaunt by bicycle should also cover the regular exercise base somewhat.

I should also say: stay off HN!