Both your nutritional needs (the food and water) and your metabolism (how fast your body converts food to energy) change at this age. Your metabolism gets slower. Women lose about half a pound of muscle per year starting around the age of 40. That makes losing weight even more difficult. Some of the changes women experience are due to decreased hormones, reduced activity level, and medical conditions.
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.”
Dairy. Women should get 3 cups of dairy each day, but most women get only half that amount.6 If you can’t drink milk, try to eat low-fat plain yogurt or low-fat cheese. Dairy products are among the best food sources of the mineral calcium, but some vegetables such as kale and broccoli also have calcium, as do some fortified foods such as fortified soymilk, fortified cereals, and many fruit juices. Most girls ages 9 to 18 and women older than 50 need more calcium for good bone health.