This is pretty strange. Do they eat less? Do they not have kids? That may be it; the rate is low in Europe.
The thought of walking to multiple shops just to buy food is a nightmare scenario to me. Considering just milk, I probably go through roughly 2 gallons (eh, 9 L) per day. I probably go through twice that much in juice. There will be a couple loaves of bread, 2 or 3 kg of meat, a hand of bananas (don't bruise them!), several large tomatos, half a kg of chocolate...
That's one day. Judging by filled grocery carts, it's about 0.2 cubic meters of stuff, a.k.a. 200 L of stuff. I think that comes to about 200 kg, given that the density of metal and glass (containers) kind of compensates for air pockets.
I could make 10 trips. Ugh. I could enlist all the little children, marching them through whatever bad weather there may be and trying not to lose any along the way. While we walk, the ice cream melts and the glass bottles get dropped. Think how many little kids would be needed to transport 200 L weighing about 200 kg.
I don't see how this is viable. Are you living on dried food? Milk powder is just not the same, and I've never even seen real juice powder. Assuming juice powder even exists, I'm sure it won't be like not-from-concentrate orange juice with extra pulp.
I'm imagining a family trudging through the winter snow in Paris. Everybody has a huge aluminum-frame hiking pack, including kids who are barely old enough to walk. To avoid losing any kids along the way, they are roped together kind of like a chain gang. It still takes multiple trips.