In 1940, a thing called Rationing begun because Hitler was shooting down ships and planes that brought food to the UK. Rationing meant everyone would get exactly the same amount of food, regardless of how much money you had. There were many rationed items during the war, but some of them were:

Unfortunately, there wasn’t much Sweets or Chocolate!!
Here is a diagram that shows you how much a person would get:

You here very lucky to get any Sweets or Chocolate at all if you got any.
Vegetables, on the other hand, you could have as many as you liked, because you can grow them in your back garden (now there’s no excuse for not eating your 5 vegetables a day.)
Petrol was also rationed. Not many people had a car back then, but the people who did could only drive 20-50 miles per week.
If you put a sign on your car saying you will offer people lifts, you would’ve got extra petrol.

Rationing: The Black Market

The Black Market was an illegal market which meant some people (not just the rich) could have more than their fair share of food.
Let me give you a little example: you went to the bakery to get some bread, and the person at the checkout purposely ‘forgot’ to take your token in, so you could have DOUBLE next week!!