Q: Is it possible to get too much sugar from eating fruit? Every day I eat an orange, apple, banana and four prunes. Often I also have about 5 tablespoons of raisins and four dates. Recently I heard a nutrition expert say that it is important to limit fruit intake to avoid harmful amounts of sugar. What do you think?

A: Fruit as a source of excess sugar is nothing to worry about. Unlike table sugar, which provides nothing but calories, the natural sugar in fruit is accompanied by generous amounts of essential vitamins and minerals, as well as fiber the body needs.

But without knowing anything about the rest of your diet or about your weight, we cannot say whether you are consuming too much fruit. To answer the question for yourself, first evaluate your diet to make sure you are getting enough of the other foods necessary to provide the full range of essential nutrients.

Second, ask yourself whether your weight is at a reasonable level. If you answered yes to both questions, there is no reason to curtail your fruit intake.

If, on the other hand, your diet plan has some serious gaps, or if you need to lose weight, consider some changes, including a cutback on fruit consumption. We calculate that your current fruit intake contributes about 560 calories to your daily tally. By eliminating the dates and raisins, you would cut back about 225 calories.

Dried fruits such as dates and raisins tend to stick to the teeth, promoting tooth decay. In the interest of preserving your dental health, it is a good idea to brush carefully after eating these fruits.

Q: I have two questions about lobsters. I have been cooking them for years, but for the first time noticed a greenish-black, viscous substance, almost resembling dirty oil, in the area where the tail and the body section joined. It appeared in two of four lobsters I cooked recently. Is it a sign of exposure to water pollution? Also, can you tell me why the lobster meat, especially in the claws, sometimes has a softer, spongy texture?

A: The greenish-black substance you observed is unrelated to pollution. At a certain point, female lobsters discharge their eggs and carry them in the tail section for nine or 10 months. When the ovulation cycle is not properly synchronized with the molting cycle, in which the animal sheds its shell for a larger one, the egg-entrusion process is disrupted and the eggs are not released.

The unreleased eggs can affect the lobster meat in different ways, depending on the stage of the ovarian cycle in which the lobster is cooked. The greenish-black viscous material you described takes its color from a protein called lipovitellin, and is simply one of the manifestations of the unreleased eggs. It in no way affects the safety or quality of the lobster.

Your question about texture relates directly to molting. Breaking out of a smaller shell into a newer one is the way that lobsters make room for tissue growth. Before molting, the flesh swells by taking on extra moisture. That makes it easier to crack the shell. Lobsters that have molted recently retain this additional water, and that alters the texture of the meat.

Q: Is it true that some vegetables have a diuretic effect?

A: No. The idea that some vegetables are "natural diuretics" has been around a long time, but is a myth. The only dietary substances normally consumed that have a diuretic effect are coffee, tea and alcohol. In the case of coffee and tea, caffeine and chemically similar substances increase the blood flow through the kidneys, thereby altering the transport of salts and water by the kidney's tubules and enlarging urinary output.

The ethanol in alcoholic beverages works somewhat differently. It depresses the production of the antidiuretic hormone. ADH, as it is called, is secreted by the pituitary and is essential for maintaining normal fluid balance. When secretion of the hormone is suppressed, as it is by ethanol, fluids are not reabsorbed. Instead they are excreted. The thirst and other symptoms often described as "the morning after" feeling are the body's signal that it needs liquid to restore fluid balance.