Like many, I was taught to bring plenty of carbs backpacking. But I've been low-carb in real life for a couple years and thought to try it on a three-night trip I took last weekend in the Strawberry Mountain Wilderness (Malheur National Forest, Oregon, USA). I brought fat and protein in the form of tinned anchovies and sardines (packed in olive oil), pouches of tuna (also in olive oil), summer sausage, beef sticks from U.S. Wellness, a little bottle of coconut oil to sip on while hiking, and so on. The only carbs were a smattering of dried blueberries added to a bag of walnut halves for a bit of trail munching.
Rather than make meals, I snacked as needed.
The gross weight of my food bag was 5-3/4 lbs (2.6 kg) when full, and 1-1/4 lbs (0.6 kg) when I returned. These weights include the bag and food packagings, so the figures are rough, but it looks like I ate about 1-1/2 lbs (0.7 kg) of food a day. I'll use this number for planning the food for my next trip.
Interestingly, I didn't develop cravings for junk food, like pizza, which I always used to do when eating the traditional carb-rich backpacking diet; I was never really hungry, I never "bonked," and I felt good with plenty of energy.