It's true that some things are worse for an older person's health than they are for a younger person's health. Sometimes the reason that an older person can't eat candy is because they have diabetes. Diabetes is when the amount of sugar in your blood gets too high. It can damage your eyes and your kidneys and slow down the blood circulation in your feet and fingers. If it's not treated it can actually kill you.

Diabetes is really one name for 2 diseases. One form of diabetes starts making a person sick when they are very young, even before they're old enough to go to school. Kids with this disease have to inject themselves with insulin every day. There's a second form of diabetes that we used to think only adults got. Now we see younger and younger people with this second kind of diabetes. People with this second kind of diabetes tend to be overweight, eat a lot of sugar and fat and not get enough exercise.

So, older people should avoid eating a lot of candy, but so should kids. What other problems are caused by eating too much candy? What kinds of things should you eat? For an answer try going to the Why Files

Should schools be allowed to sell sugary soda?

Food gives us energy, just like gas gives our cars energy to run. The energy is measured in calories. But we need to eat things besides just energy if we want to be healthy. Some of those things are minerals, such as iron and calcium, and vitamins. (The gas for our cars has 'additives,' too, to make our cars run better. That's what lead did in our gas.) The good foods on the Food Pyramid have energy and vitamins and minerals - including vitamins that haven't been discovered yet, because we need more than just the vitamins in vitamin pills.

Scientists named the calories in candy "empty calories." That means they're calories that come from foods without vitamins and minerals. So your grandfather needs to eat things besides candy, but a lot of people also live to very old ages even if they do some things that aren't very healthy.