Yes, food is a significant portion of energy consumption, but typical transportation and housing (including heat/cool) easily dominate. Going from a daily mixed meat (chicken/fish/beef/eggs) eating diet to a vegan diet saves ~1 ton CO2 per year. Average is about 4-5 tons per year for a person living in a small apartment in temperate climate, who only uses public transportation, doesn't go on vacation, or buy any unnecessary consumer items. A more typical westerner who can afford meat every meal is about 10-20 tons per year.
Now, if you're eating 150g of beef every meal 3x every day, you could double your footprint (+20tons CO2). Eating only chicken, fish, and eggs gets you below 1ton/year for meat in meals. Vegan is about a third of that.
https://8billiontrees.com/carbon-offsets-credits/carbon-ecol...
[1]https://css.umich.edu/publications/factsheets/sustainability...
Have you tried arguing people against eating meat? If we can't even talk them out of the main individual contributor to climate change, I don't think we have a good chance to make a positive impact on other areas that depend on conscious effort.