6 Feb 2012, 1:40am
General Nutrition
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  • Daily Nutritional Needs: How Much to Eat and Why


    There’s no such thing as an appropriate caloric intake that fits everybody. The numbers vary greatly from one person to the next, based on size, age, sex and activity level. Your body composition also affects how much you should eat. The more muscle you have, the more calories you burn, even at rest. This means you can eat more calories and still maintain your weight.

    The FDA does provide very general guidelines based on age and sex, but this should not be taken as definitive, since they don’t take into consideration how active you are. According to the FDA, adult women (between 19 and 50 years of age) should eat about 1,950 calories, while adult men should eat about 2,500.

    Weight Loss and Calories

    If you’re trying to lose weight, the appropriate caloric intake will be much different. As a general rule, you need to cut 500 calories from your diet every day in order to lose 1 lb. per week. If you want to lose 2 lbs. per week, you’d have to cut 1,000 calories from your diet.

    Your BMR (or basal metabolic rate) is the amount of energy your body uses when at rest. This means you need a minimum of daily calories for the functioning of your lungs, digestive system, muscles and more. Again, these numbers vary depending on your size, but experts recommend eating a minimum of 1,200 calories even if you’re trying to lose weight. Crash diets that cut your calorie intake to fewer than 800 calories per day have a negative impact on your metabolism. When you don’t eat enough to meet the minimum required by your body, your metabolism will slow down to compensate for the difference. A slower metabolism leads to slower weight loss and a number of other problems.

    Daily Calorie Burning

    Weight loss through exercise alone is difficult. This is because to achieve a daily calorie burning of 500 calories, you would have to do cross country skiing, run (at least 5 mph), mountain bike or play field hockey for at least an hour seven days a week. Moderate exercise such as riding the stationary bike, doing yoga or taking a low-impact aerobics class won’t burn enough to produce a significant difference on the scale in a single week.

    Daily Vitamin and Mineral Requirements

    Your daily vitamin needs are affected by your age and sex (but not your weight). In most cases, men needs slightly more of all vitamins than women do. Some vitamins, however, don’t have different recommended intakes for men and women. For example, men need about 625 mcg of vitamin A per day, while women need 500 mcg. However, both men and women need about 2 mcg of vitamin B12 a day.

    Needs change during pregnancy and lactation, as well as for teens and children.

    People who eat a balanced diet should be able to obtain all the vitamins and minerals they need from food. In many cases, however, this is simply not possible, especially if you don’t eat enough fruits and vegetables on a daily basis. Vegetarian nutritional requirements can also be different. This is especially true in the case of vegans, who don’t consume any animal products. Since vitamin B12 is only found in animal products, strict vegetarians might need supplementation in order to stay healthy. Vegetarians could also suffer calcium and iron deficiencies. These can be addressed by taking supplements or by increasing the amount of dark green leafy vegetables and sea vegetables in the diet.

    Understanding the Nutrition Information Label

    The nutrition information label can give you a glimpse into what you’re eating (and what you’re missing), but only if you learn to read it properly. Probably the most important part of the label is the “serving size.” In most cases, you get several servings per container of anything you buy. For example, a pack might contain 20 cookies but the serving size is only 2 cookies. This means all the numbers you see on the label will be about those 2 cookies. If you eat the whole package, you’ll need to multiply all the numbers by 10.

    When you look under “Amount Per Serving,” the two most important numbers are Saturated Fat and Sugars. The recommended maximum intake of sugar is 25 grams per day. A single can of Coke contains 39 grams of sugar, so you can see how easily those numbers stack up.

    Our bodies need fat in order to absorb certain vitamins and nutrients, so going completely fat-free is not a good idea. However, your body does NOT need saturated fat, so if you cut all animal fats from your diet and only eat unsaturated (vegetable fat), you’ll be perfectly fine. A person on a 2,000 calorie diet should eat a maximum of 22 grams of saturated fat per day. A 4-oz. piece of cheddar cheese contains 24 grams of saturated fat, while a 6-oz serving of lean ground beef contains 11 grams of saturated fat.

    If you focus on eating a healthy, moderate diet that includes all food groups, you should have no problem meeting your daily nutritional requirements and keeping your weight stable.