Science seems to support Mark Twain’s contention that “The only way to keep your health is to eat what you don’t want, drink what you don’t like, and do what you’d rather not.”

And as you reach your mid-50s, the consequences of ignoring nutrition and exercise become far more pointed.

There is good news. According to the U.S. Food and Drug Administration, nutrition can lessen the effects of many diseases, including osteoporosis, diabetes, high blood pressure, heart disease, gastrointestinal problems, obesity and certain cancers. The FDA’s Web site states, “good diet in later years helps both in reducing the risk of these diseases and in managing the diseases’ signs and symptoms.”

But there’s bad news, too. Poor nutrition “can prolong recovery from illnesses, increase the costs and incidence of institutionalization and lead to a poorer quality of life.”

As people age, their needs and tastes change says dietitian Julie Walker of the Humphreys Diabetes Education Center in Meridian, Idaho. “If we don’t exercise we lose five to seven pounds of muscle every decade, so we need fewer calories,” she says. “We need to be more selective.”

At a certain point, people find “there’s less of a desire for red meat, and that’s a good thing,” she observes. “But they also lose some of their taste buds, and that’s a bad thing because they gravitate to foods with a lot of salt, and everybody eats too much salt. You can’t eat anything out of a box, a can or a restaurant without getting too much salt,” a key factor in high blood pressure and other health problems affecting seniors.

The American Institute for Cancer Research suggests that people over 50:

Pay attention to portions. Find serving size information on the Nutrition Facts panel of a food label. There are a number of simple tricks for estimating a portion: a deck of cards (serving a meat), fist (cup of mashed potatoes), light bulb (serving of fruit), egg (quarter-cup of dried fruit), computer mouse (medium baked potato), baseball (half-cup of pasta).

A wealth of information, as well as ways to customize diets, can be found on a U.S. Department of Agriculture Web site, www.mypyra mid.gov.

Cut down on fat. Some fat is essential, but be especially wary of saturated fats (found in animal products) and trans fats.

Get your fats from vegetable oils such as canola or olive that are high in monosaturated fat and low in saturated fat. Use soft tub margarine or squeeze spreads that have little saturated fat and no trans fat.

Drink up. Consume eight glasses of water each day.

Enjoy what you eat. Eat slowly and savor every bite.

Keep active to help burn calories. Be physically active every day for half an hour or longer.

Once you pass 50, calories assume more importance. The National Institute of Aging recommends that a woman older than 50 consume between 1,600 and 2,200 calories per day, depending on activity level; a man should consume between 2,000 and 2,800 calories daily.

One way to track progress is to keep a food journal in which you note everything you eat, the time you eat it and portions. By reviewing the journal each evening you can get a handle on your habits.

Dietitian Julie Walker recommends three Web sites for those seeking healthful dietary information: www.sparkpeople.com, www.nutritiondata.com and www.healthydiningfinder.com.

Before your food hits the table, make a point to check the label

If we are what we eat, then the nutrition facts label is our table of contents. The label, which is found on nearly every package of food, outlines nutrients in grams or milligrams and as a percentage, based on a 2,000 calorie per day diet. Starting from the top:

Serving size

Includes what constitutes one serving and how many servings are in the package.

Calories and calories from fat

Calories per serving are on the left; on the right is the number of calories from fat.

Percent daily value

Percentages are based on the recommended daily allowance in each category. Some values, such as those for carbohydrates, proteins and fat, are based on caloric needs. Others, such as for sodium, minerals and vitamins, are the same for everyone.

Total fat

The total fat is the number of fat grams contained in one serving of the food; various types of fat —

saturated, unsaturated and trans fat — are listed as sub-items.

Cholesterol and sodium

How many milligrams of cholesterol and sodium (salt) are in a single serving.

Total carbohydrates

This number tells you how many carbohydrate grams are in one serving broken down into grams of sugar and grams of dietary fiber.

Protein

This number tells you how much protein you get from a single serving of the food.

Vitamin A and vitamin C

These list the amounts of vitamin A and vitamin C, two key vitamins, in a

serving of the food. Each amount is given as a percent daily value.

Calcium and iron

These list the percentages of calcium and iron, two important minerals, which are given as a percent daily value.

Calories per gram

These numbers show how many calories are in one gram of fat, carbohydrate and protein. This information is the same for every food and is printed on the food label for reference. — copley news service