The ketogenic diet is based on the process of ketosis, which is characterized by high levels of ketones in the blood that occur during the conversion of fats into fatty acids and ketones. The diet encourages the body to use ketones stored in fat cells more efficiently for energy, according to Diet Ketogenic.

Calzones aren't exactly healthy food, especially if they are stuffed with meat and large amounts of cheese. A calzone typically uses the same amount of pizza dough as a pizza crust and is meant to serve four people. Eating a whole calzone yourself can mean eating more than your recommended calories for the day.

Made from brined grape leaves, rice, lemon and aromatic herbs, stuffed grape leaves -- also called dolmades -- make a zesty side dish or snack.

With its nutritious bean sprouts, thin noodles and lean tofu, pad Thai may seem like a healthy choice; however, the calories can add up quickly in large restaurant portions. If you finish your whole plate, you'll have consumed about 940 calories, which is typically too many for a single meal.

Pad Thai, a signature dish of Thailand, is made with rice noodles, tofu, peanuts, vegetables, sugar and chilies, and often contains shrimp. Served plain, the noodles in pad Thai contain about 190 calories per cup after boiling.

Aromatic and warm, a steaming bowl of vegetable pho makes a healthy and soothing lunch on a cold day. While this Vietnamese noodle soup is relatively low in calories -- thanks to the broth base and lean ingredients -- you still need to watch portion sizes.

Hibachis are charcoal-style grills which originated in Japan in the 1800s, according to Merriam-Webster’s online dictionary. Hibachi-cooked food is a popular choice in Asian restaurants. Hibachi-cooked food also happens to be a good choice for the calorie-conscious.

Taco salad shells are typically deep-fried, which makes them fairly heavy on calories. Pair them with ingredients like ground beef, cheddar cheese, sour cream and guacamole, and you could end up eating more than 1,000 calories in a single salad.

A glass rimmed with salt is the carrier for a margarita -- a sweet and creamy beverage made from tequila, sour mix, triple sec, lime juice and sugar. Though the drink seems light and refreshing, its taste is deceptive. Frozen margaritas -- blended with crushed ice or served "on the rocks"

If you have a hankering for Japanese fare and are watching your weight, vegetable sushi is a healthy choice because most vegetables are extremely low in calories. If you include avocado in your sushi, however, stick to thin slices. Avocados are much higher in fat and calories than most other fruits and vegetables.

1800's Ultimate Margarita comes premixed, so there's no need to add your own tequila. 1800 suggests pouring it over ice or blending it with ice to enjoy the beverage. A 4-ounce serving comes in at 130 calories, about the same number of calories as a 12-ounce can of beer or 5-ounce serving of red wine.

Older adults often do not get the calories or nutrition they need due to decreased appetite and decreased mobility. Rapid weight loss is common after age 70 and can result in health problems.