The guidelines also establish ranges (called acceptable macronutrient distribution ranges or AMDR) for fat, carbohydrates and protein, instead of exact percentages of calories or numbers of grams. The report maintains that since all three categories serve as sources of energy, they can, to some extent, substitute for one another in providing calories.
Don't take dramatic steps alone. You need to work closely with an experienced health care professional to lose weight, particularly if you have other medical problems, plan to lose more than 15 to 20 pounds or take medication on a regular basis. An initial checkup can identify conditions that might be affected by dieting and weight loss. Make sure you find out how much experience your health care professional has dealing with nutrition. It's not always well covered in medical schools. You may want to talk to a registered dietitian before embarking on a diet.
There's not much doubt about this one: Women need more iron than men, because they lose iron with each menstrual period. After menopause, of course, the gap closes. The RDA of iron for premenopausal women is 18 mg a day, for men 8 mg. Men should avoid excess iron. In the presence of an abnormal gene, it can lead to harmful deposits in various organs (hemochromatosis). Since red meat is the richest dietary source of iron, it's just as well that men don't need to wolf down lots of saturated fat to get a lot of iron.

Fluids: Fluid needs increase as women age. The reason: Kidneys become less efficient at removing toxins. “Drinking more fluids helps kidneys do their job,” Schwartz says. “Unfortunately, thirst signals often become impaired with age, so people are less likely to drink enough water and other fluids.” Rather than fret about how many glasses to drink, Frechman says, check the color of your urine. "It should be clear or very pale colored. If it becomes darker, you need more fluid.”