Survival Industry makes use of Hunger Overhaul, Hunger in Peace, and Spice of Life to add to the challenge, and AgriCraft and Pam's Harvestcraft to help survive the challenge.
Hunger is a real threat in the early-game. Everything uses an amount of hunger; running, jumping, swinging a weapon... even standing still or sleeping. To make matters worse, food's ability to satisfy hunger is much less than it was in the vanilla game. And peaceful mode is no escape from hunger; it will continue to drop even if you are in peaceful mode. On a side note, peaceful also no longer has a insta-regen feature. All peaceful can do now is remove hostile mobs.
Pam's Harvestcraft helps to mitigate this issue by providing a huge number of crops and recipes to keep you from eating the same thing too much. Agricraft allows you to improve your harvest, or even get seeds to crops you don't already have.