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.
A spokesperson for optimal nutritional intake is the well-known biochemist Bruce Ames, who proposed the "triage theory of nutrients," in which enzymes responsible for cell maintenance functions evolved to have lower affinity for the essential vitamin and mineral cofactors than the enzymes responsible for short-term survival, to preserve life during times of famine. 
What you eat and drink is influenced by where you live, the types of foods available in your community and in your budget, your culture and background, and your personal preferences. Often, healthy eating is affected by things that are not directly under your control, like how close the grocery store is to your house or job. Focusing on the choices you can control will help you make small changes in your daily life to eat healthier.
Although as a general rule, dietary supplement labeling and marketing are not allowed to make disease prevention or treatment claims, the U.S. FDA has for some foods and dietary supplements reviewed the science, concluded that there is significant scientific agreement, and published specifically worded allowed health claims. An initial ruling allowing a health claim for calcium dietary supplements and osteoporosis was later amended to include calcium supplements with or without vitamin D, effective January 1, 2010. Examples of allowed wording are shown below. In order to qualify for the calcium health claim, a dietary supplement much contain at least 20% of the Reference Dietary Intake, which for calcium means at least 260 mg/serving.
Something else to remember: an estimated 90 to 95 percent of dieters who lose weight regain all or part of it within five years, and the consequences can be even worse than simply being overweight. Those who exercise regularly as part of a weight loss diet and maintenance program are more likely to keep the weight off. Also note that an overly restrictive diet can lead to more overeating, a natural reaction to food deprivation.
In general, the FDA regulations for dietary supplements are different from those for prescription or over-the-counter drugs. Unlike drugs, which must be approved by the FDA before they can be marketed, dietary supplements do not require premarket review or approval by the FDA. While the supplement company is responsible for having evidence that their products are safe and the label claims are truthful and not misleading, they do not have to provide that evidence to the FDA before the product is marketed.
All youth need calcium to build peak (maximum) bone mass during their early years of life. Low calcium intake is one important factor in the development of osteoporosis, a disease in which bone density decreases and leads to weak bones and future fractures. Women have a greater risk than men of developing osteoporosis. During adolescence and early adulthood, women should include good food sources of calcium in their diets This is when bone growth is occurring and calcium is being deposited into the bone. This occurs in women until they are 30 to 35 years of age. Women 25 to 50 years of age should have 1,000 mg of calcium each day, while women near or past menopause should have 1,200 mg of calcium daily if they are taking estrogen replacement therapy; otherwise, 1,500 mg per day is recommended. Women older than 65 years of age should have 1,500 mg per day.
In 1994, the United States Congress passed a law defining nutritional supplements, and requiring them to be labeled as dietary supplements and identified as not intended to be a substitute for certain foods. A nutritional supplement can be defined as a product intended for consumption in tablet, capsule, powder, soft gel, gel cap, or liquid form, and containing vitamin(s), mineral(s), herb(s), other botanicals, amino acids, or any combination thereof.
Without the energy you get from things like carbohydrates, your blood sugar levels will likely dip which may lead you to feel sluggish and fatigued. And if you let yourself get to hungry, Rachele Pojednic, Ph.D., assistant professor in the nutrition department at Simmons College and professor at the Harvard Extension School, tells SELF that appetite-inducing hormones like ghrelin may even cause you to become shaky or sweaty.
Dietary supplements are substances you might use to add nutrients to your diet or to lower your risk of health problems, like osteoporosis or arthritis. Dietary supplements come in the form of pills, capsules, powders, gel tabs, extracts, or liquids. They might contain vitamins, minerals, fiber, amino acids, herbs or other plants, or enzymes. Sometimes, the ingredients in dietary supplements are added to foods, including drinks. A doctor’s prescription is not needed to buy dietary supplements.
The dietary supplements industry in the United Kingdom (UK), one of the 28 countries in the bloc, strongly opposed the Directive. In addition, a large number of consumers throughout Europe, including over one million in the UK, and various doctors and scientists, had signed petitions by 2005 against what are viewed by the petitioners as unjustified restrictions of consumer choice. In 2004, along with two British trade associations, the Alliance for Natural Health (ANH) had a legal challenge to the Food Supplements Directive referred to the European Court of Justice by the High Court in London.
In addition to diet, exercise and other lifestyle factors can also play an important role in bone health. Smoking and drinking too much alcohol can increase your chances of developing osteoporosis, while weight-bearing exercise (such as walking, dancing, yoga, or lifting weights) can lower your risk. Strength or resistance training—using machines, free weights, elastic bands, or your own body weight—can be especially effective in helping to prevent loss of bone mass as you age.