This pack makes use of the "unholy trinity" of survival mods; Hunger Overhaul, Spice of Life, and Pam's Harvestcraft.  Starvation is a very real threat and farming must be started as soon as possible.  If you are unfamiliar with these mods, Hunger Overhaul causes hunger to deplete faster, food restores less hunger, plants and animals grow slower, and total depletion of the hunger bar causes instant death.  Spice of life requires the player to eat different foods or face diminishing returns on how much hunger/saturation is restored by those foods.  The food cycle in this pack is 128 items long before the first food the player has eaten is restored to it's original value. New players are provided with a grace period of 72 pieces of food before this effect kicks in.  Use this time wisely, it will be over before you know it.  Start farming ASAP. Also be aware that your "food history" persists through death in this pack and is being computed during your grace period, so running out of usable foods presents a major long term problem.

Hunger Overhaul does provide one very nice benefit to players.  You will continue regenerating your health as long as your current hunger level is not "Starving".  The current level of hunger is displayed in the top right of the screen.  Once your hunger starts getting dangerously low, you will start getting hit with negative status effects like slowness and mining fatigue.  The same is true for injury, loosing a substantial amount of health will afflict you with various debuffs.

If the hunger mechanics sound daunting, then worry not.  Harvestcraft is the way you survive this challenge.  It provides you with a massive array of new crops and dishes to prepare.  Look for Harvestcraft "gardens" when you are starting out, breaking these will give the player three random foood items that depend on the type of garden broken.  You can then craft these crops in your inventory to get the seeds for those foods.  This pack also uses Agricraft style farming.  You will need to craft crop sticks for every piece of tilled soil.  Weeds are enabled, so leaving crop sticks on plots with nothing planted will allow weeds to take hold, and they can and will uproot low level seeds.

Finally, if you should happen to find some high tier HarvestCraft food items as loot while exploring the world during your Spice of Life grace period, this is the best time to make use of them.  You will not be able to produce "feast" or similar high quality meals for quite a while and having access to them will greatly extend the amount of real gameplay hours your grace period will last for.  On this note, new players will be given five epic bacons to start out with to help you ease into the difficulty.  

If you are feeling daunted or confused by the number of foods that exist in the pack, be sure to make use of Cooking for Blockheads, it will show you what foods you can make from ingredients in your inventory.  It also provides you with useful and stylish kitchen appliances for your base.