Yes Arnold, I carry a complete tent, including a footprint and stakes. Just because the fly alone resides in the front pocket of my pack doesn't mean I lied about carrying the rest of the tent. Did I really have to explain that?
Yes, you do have to explain that, because your weight just doesn't add up.
Regarding food weight, you might want to look into getting yourself a dehydrator.
That still gonna get you a 4:1, maybe 5:1 calorie to gram ratio. So around 2250 calories a day. Unless you're a midget or hike for the entire 300 meters a day, you will starve. And forget about having any luxuries on your trip, like boiled eggs and hot dogs.
I can pretty safely assume the rest of your gear repertoire is similar in nature to your food - just barely enough to survive.
Go over to the backpackinglight.com board and post that you think it's impossible to do a 4-day hike with a total load of 16.5 lbs. You'll find a ton of folks who do it with significantly less weight. My 16.5 lbs is barely at the fringes of UL backpacking.
I don't need to go over some crazies board, where they brag to each other how much they can torture themselves. In that case, I can hike in a t-shirt and shorts, with a water bottle in my hand. I will sleep under leaves and eat grass all day. Why not? Why would I carry 16.5 lbs on my back?
If you need a 90+L pack for backpacking 5-8 days, that's entirely your choice. Best of luck with it.
Heck, I'll carry that bag for 1 night. As long as the bag is comfortable and supports the weight well, it's not an issue at all. I'll have enough warm clothes, eat well, and sleep in a roomy tent on a relatively thick mattress without shivering at night. Also, my toothbrush won't be cut in half in the morning.