Yeah, I usually go with much less than 2pounds (about .9kg) per day. I usually head out with around 425g/day or around a pound/day.
A typical breakfast is about 2oz of oatmeal of assorted flavors. 3 cups of mocha.
I stop a couple times to eat about a half of a energy bar, some cheese, jerky or similar. A light snack to keep me moving past 8 hours.
I usually eat about a 7oz supper with an 2ounces of pemmican, or an ounce of olive oil and an ounce of dried meat, and, a cup of cocoa (sometimes an ounce of “trail fuel”… )
All told, around 0.9-1.1 pounds per day, avg. on a 14 day trip. You cannot really metabolize body fat fast enough to supply all of your energy needs, so, while I could go with less (I have tried 0.75pounds per day) I find that I get tired, required more rest stops, and am done about 8 hours into the next day.
The rest of my energy is from fat from my body. In cold weather I sometimes pack a bit more, for example adding some chocolate/peanut bars for more energy output.
Most of your fat reserves are metabolized at a fairly constant 2500C/day. This varies from person to person, with training, with your condition, your age… For example, Eskimo peoples were known to eat 80% fats in their diet and utilize most of it as part of a 4500C diet. Each pound of fat has about 3200C (some say more, but only the lipids are used, not the entire cell, and, it costs energy to get energy from stored fats.) Bomb calorimeters burn everything, for example, without considering the cells still need to live. So, it is possible to burn about 3/4 of a pound (about a 1/3 of a kg) with no ill effects provided you have some food and the vitamins/minerals needed to maintain your metabolism. In slack season, I have been known to put on about 20 pounds of reserve. By late fall, I will have lost it. On a two week trip, I usually plan on loosing 5-8 pounds. Bodily fat reserves are the way your body beats lean times. This goes back for thousands of years, maybe millions, before man was homo sapiens. I just “force” this to happen.
The metabolism of fats normally occurs simultaneously, ie the in and out are balanced. Fatty acids are stored in fat cells and released from fat cells. The concentrations of various hormones doesn’t mean just because one is low it has NO effect. It is the difference between the two that says we add or subtract weight, similar to thermodynamics in that regard.
What your body does NOT expect, is the sudden cessation of food. This will cause you to loose energy, metabolize muscles for energy, and so on after a couple days. By eating a reduced amount of food, you won’t cause this bodily “panic” by going into starvation mode, rather it is just one of those “lean times” it is naturally prepared for. But, cutting into that balance and making it work with you can be tricky.
Unless you know how your body will react, I would suggest staying with at least 1/2kg of food. I spent over 40 years rarely eating lunch, and, mostly just having coffee for breakfast. This means I usually only really eat once per day. If you are a three or four meal per day person, this type of diet could be a real problem for you. You might find that you are “hungry” all the time. When I go hiking, I eat three or four times a day, close to 2500-2700C/day intake, but on a different, much broader schedule. I usually eat around 2000-2200C/day at home. I eat 4-5 times per day, while hiking.
My energy expenditure goes way up. I go from 2200C/day to 4000C/day or more. What I eat changes. I eat more proteins. Dried beef, jerky, pemmican, chocolate, peanuts, dried milk, etc all have rather high protein content. This protects my muscles from breakdown. My fat intake is up, often adding olive oil or ghee to my morning oatmeal/mocha. This helps with long term energy (>4 hours.) Carbs are mostly starches (rice, macaroni, oatmeal, sucrose, etc.) This helps with short term energy (0-4 hours.) Also at home, I have fresh fresh fruits/vegies, but hiking, none. I take a vitamin/mineral once per day out hiking. It is lighter. Multiple small meals insures I have enough starches/sugars to burn fats efficiently.
Anyway, my recommendations? For short trips you can safely reduce the amount of food carried by 2:1 to a maximum of a 1/2pound of fat reserve provided you maintain a balanced diet in all other respects and have an average food density of 127C/oz. Ummmm…you can play with the conversions. Or in metric, if you need 1kg/day, you can reduce this to .5kg/day and use .25kg per day in bodily reserves. Note that this is the MAXIMUM reserve you can use. Likely, it is closer to 0.34Kg, but this might not be good if you have no conditioning.
References:
A lot of this is more or less correct, but not in specifics. It is still a good overview if nothing else: https://learn.genetics.utah.edu/content/metabolism/bbs/
This is better, but more complex: https://www.unm.edu/~lkravitz/Article%20folder/physiologgfatloss.html
I had planned to list a lot more but most of this was written by sports/diet wichdoctors. There is a Lot more and a lot of misinformation on the web, be VERY careful. Wikopedia has a very poor reference on fats/metabolism…It is self contradictory…