Adulthood begins at the end of adolescents and continues until the end of one’s life. The human body will reach maximum cardiac output during adulthood, specifically between ages twenty and thirty. Bone and muscle mass also reach optimal levels, and physical activity improves muscle strength, endurance, and tone. Besides physical activity, nutrition also plays an essential role in maintaining health through adulthood. As you’ve already learned, a healthful diet includes a variety of nutrient-dense foods. Consuming diets high in fruits and vegetables offers health benefits such as a reduced risk for heart disease and protection against certain cancers.

YOUNG ADULTHOOD

Young adulthood is the period from ages nineteen to thirty years. Physical growth has been completed, and all organs and body systems are fully developed. Typically, an active young adult has reached their physical peak and is excellent. For example, vital capacity, or the maximum amount of air that the lungs can inhale and exhale, is peaked between twenty and forty. During this life stage, it is important to continue to practice good nutrition. An adult’s body does not need to devote its energy and resources to support the rapid growth and development that characterizes youth. However, the choices made during those formative years can have a lasting impact. Eating habits and preferences developed during childhood and adolescence influence health and fitness into adulthood. Some adults have gotten a healthy start and have established a sound diet and regular activity program, which helps them remain in good condition from young adulthood into the later years. Others carry childhood obesity into adulthood, which adversely affects their health. However, it is not too late to change course and develop healthier habits and lifestyle choices.

Energy and Macronutrients

Young men typically have higher nutrient needs than young women. Women’s energy requirements are 1,800 to 2,400 calories and 2,400 to 3,000 calories for men, depending on activity level, for ages nineteen to thirty. These estimates do not include pregnant or breastfeeding women who require a higher energy intake. For carbohydrates, the AMDR is 45 to 65 percent of daily calories. All adults, young and old, should eat fewer energy-dense carbohydrates and incredibly refined, sugar-dense sources, particularly those who lead a more sedentary lifestyle. The AMDR for protein is 10 to 35 percent of total daily calories and should include a variety of lean meat and poultry, eggs, beans, peas, nuts, and seeds. The guidelines also recommend that adults eat two 4-ounce servings (or one 8-ounce serving) of seafood per week.

All adults should limit total fat to 20 to 35 percent of their daily calories and keep saturated fatty acids to less than 10 percent of total calories by replacing them with monounsaturated and polyunsaturated fatty acids. It is also important to replace proteins high in trans fats and saturated fat with lower solid fats and calories. Avoid trans fats by limiting foods that contain synthetic sources, such as partially hydrogenated oils. Soluble fiber may help improve cholesterol and blood sugar levels, while insoluble fiber can help prevent constipation. The AMDR for fiber is 22 to 28 grams per day for women and 28 to 34 grams per day.

Micronutrients

Micronutrient needs in adults differ slightly according to sex. Males need more vitamins C and K, along with thiamine, riboflavin, and niacin. Young men and women who are very athletic and perspire a great deal also require extra sodium, potassium, and magnesium. Females require extra iron due to menstruation. Therefore, it can be beneficial for some young adults to follow a daily multivitamin regimen to help meet nutrient needs. But as always, it is important to remember “food first, supplements second.

middle age

Middle age is defined as the period from age thirty-one to fifty. The early period of this stage is very different from the end. For example, many women experience pregnancy, childbirth, and lactation during the early years of middle age. In the latter part of this life stage, women face perimenopause, a transition period leading up to menopause or the end of menstruation. Several physical changes occur in the middle-aged years, including the loss of bone mass in women due to dropping estrogen levels during menopause. In both men and women, visual acuity declines, and by age forty, there can be a decreased ability to see objects at a close distance, a condition known as presbyopia. During this stage of the human life cycle, adults begin to experience the first outward signs of aging. Wrinkles start to appear, joints ache after a highly active day, and body fat accumulates. There is also a loss of muscle tone and elasticity in the connective tissue. In their late thirties and their forties, many people notice a decline in endurance, the onset of wear-and-tear injuries (such as osteoarthritis), and changes in the digestive system. Wounds and other injuries also take longer to heal. Body composition changes due to fat deposits in the trunk. To maintain health and wellness during the middle-aged years and beyond, it is important to:

• maintain a healthy body weight
• consume nutrient-dense foods
• drink alcohol in moderation
• don’t smoke
• engage in moderate physical activity at least 150 minutes per week

Energy and Macronutrients

The energy requirements for ages thirty-one to fifty are 1,800 to 2,200 calories for women and 2,200 to 3,000 calories for men, depending on activity level. These estimates do not include women who are pregnant or breastfeeding. Middle-aged adults must rely on healthy food sources to meet these needs. Following the middle-aged years,’ dietary guidelines provide adequate but not excessive energy, macronutrients, vitamins, and minerals. Typical dietary patterns in many parts of North America do not match the recommended guidelines.

The AMDRs for carbohydrates, protein, fat, fiber, and fluids remain the same from young adulthood into middle age. It is important to avoid putting on excess pounds to help prevent cardiovascular disease, diabetes, and other chronic conditions.

Micronutrients

There are some differences, however, regarding micronutrients. For men, magnesium’s recommendation increases to 420 milligrams daily, while middle-aged women should increase their magnesium intake to 320 milligrams per day. Other essential vitamins needed during the middle-aged years include folate and vitamins B6 and B12 to prevent the elevation of homocysteine, a byproduct of metabolism that can damage arterial walls and lead to atherosclerosis, a cardiovascular condition. Again, it is essential to meet nutrient needs with food first, then supplementation, such as a daily multivitamin, if you can’t meet your needs through food.

Preventive Nutrition

Preventive nutrition is defined as dietary practices that reduce disease and promote health and well-being. During the middle-aged years, preventive nutrition can promote wellness and help organ systems to function optimally throughout aging. Healthy eating in general—such as eating unrefined carbohydrates instead of refined carbohydrates and avoiding trans fats and saturated fats—promotes wellness. However, there are also some things that people can do to target specific concerns. One example is consuming foods high in antioxidants, such as strawberries, blueberries, and other colorful fruits and vegetables, reducing cancer risk.

Phytochemicals are also great nonessential nutrients that may promote body wellness. For example, carotenoids, which are found in carrots, cantaloupes, sweet potatoes, and butternut squash, may protect against cardiovascular disease by preventing the oxidation of cholesterol in the arteries. According to the American Cancer Society, some studies suggest that a phytochemical found in watermelons and tomatoes called lycopene may protect against stomach, lung, and prostate cancer, although more research is needed.

Omega-3 fatty acids can help to prevent coronary artery disease. These crucial nutrients are found in oily fish, including salmon, mackerel, tuna, herring, cod, and halibut. Other beneficial fats vital for healthy functioning include monounsaturated fats found in plant oils, avocados, peanuts, and pecans.

Menopause

In the middle-aged years, women undergo a specific change that significantly affects their health. They begin the process of menopause, typically in their late forties or early fifties. The ovaries slowly cease to produce estrogen and progesterone, which results at the end of menstruation. Menopausal symptoms can vary, including hot flashes, night sweats, and mood changes. The hormonal changes during menopause can lead to many physiological changes, including alterations in body composition, such as weight gain in the abdominal area. Bone loss is another common condition related to menopause due to losing female reproductive hormones. Bone thinning increases the risk of fractures, affecting mobility and the ability to complete everyday tasks, such as cooking, bathing, and dressing.

Recommendations for women experiencing menopause or perimenopause (the stage just before the end of the menstruation) include:

• consuming a variety of whole grains and other nutrient-dense foods
• maintaining a diet high in fiber, low in fat, and low in sodium
• avoiding caffeine, spicy foods, and alcohol to help prevent hot flashes
• eating foods rich in calcium, or taking physician-prescribed calcium supplements and vitamin D
• incorporating stretching exercises to improve balance and flexibility and reduce the risk of falls and fractures

Obesity

Obesity remains a primary concern in young adulthood. A BMI above 25 is considered overweight for adults, and a BMI of 30 or higher is obese. By that measurement, about two-thirds of all adults in the United States are overweight or obese, with 35.7 percent considered obese. Physical inactivity and poor dietary choices during childhood and adolescence are significant contributors to obesity in adulthood. Therefore, it is important to limit unrefined carbohydrates and processed foods.