Strawberries are a good source of Vitamin C and are low in calories.

An apple a day just doesn’t cut it anymore, and too many apples can contribute to weight gain.

So says Iva Young, a nutritional expert who warns that some fruits might not be as healthy as you think they are.

“We really should be smart about the fruits we consume,” said Young, author of Healthy Mom. “Remember that fruits are very similar to breads, pastas, rice, and other carbohydrate-rich foods. That is one reason why we should only consume a certain amount, and choose fruits that are lower in sugar. If you pick the right fruits and eat the proper portions, you will give your body what it needs.”

So which fruits offer the biggest health boost? Young named the following, all comparatively low in sugar, as her top five:

Raspberries -- Raspberries are an excellent source of fiber, offering 30 percent of our recommended daily value of 8 grams per serving. Raspberries are also a rich source of vitamin C, with about 50 percent of our daily value. In addition, they are a rich source of manganese, delivering 60 percent of what we should have each day. Raspberries rank near the top of all fruits for antioxidant strength and contain many anti-disease properties if consumed regularly.

Blackberries -- Blackberries are notable for their high nutritional contents of dietary fiber, vitamin C, vitamin K, folic acid, and manganese. They are well-ranked for having strong antioxidant levelsand contain copious amounts of omega-3 and omega-6 fatty acids.

Kiwi -- Kiwi is a rich source of vitamin C and vitamin K, which is a natural blood thinner. It’s also a good source of potassium, just slightly less than that of a banana. Potassium is one of those nutrients that’s absolutely essential for heart health, yet many people don’t get nearly enough. Kiwi also delivers a mild laxative effect, possibly because of the high level of dietary fiber.

Strawberries -- Strawberries are low in calories compared to many other fruits, and are a good source of fiber. They are an excellent source of vitamin C and flavonoids, promoting lots of antioxidant activity in the body.

Oranges -- Oranges are an excellent source of vitamin A and C, along with antioxidants. Oranges also provide a good source of fiber when the pulp is consumed. The white pith of the orange contains flavonoids, and some doctors are using extracts from the pith to help fight certain types of cancer.

“Sugar is also something that you should keep your eye on because it affects the health of your teeth and the functioning of your hormones, specifically leptin,” Young said. “Leptin is the important hormone responsible for telling the body that you should stop eating. With excess amounts of sugar in your body, the amount of leptin is diminished, which causes you to overeat."