One of the best ways to have a healthy diet is to prepare your own food and eat in regularly. Pick a few healthy recipes that you and your family like and build a meal schedule around them. If you have three or four meals planned per week and eat leftovers on the other nights, you will be much farther ahead than if you are eating out or having frozen dinners most nights.
Nutrition is particularly important during pregnancy to ensure your health and the health of the baby. It's normal to gain weight during pregnancy—not just because of the growing fetus, but because you'll need stored fat for breast-feeding. The Institute of Medicine (IOM) recommends a gain of 25 to 35 pounds in women of normal weight when they get pregnant; 28 to 40 pounds in underweight women; and at least 15 pounds in women who are overweight when they get pregnant. The IOM has not given a recommendation for an upper limit for obese women, but some experts cap it as low as 13 pounds. If you fit into this category, discuss how much weight you should gain with your health care professional.
Vitamins are micronutrients, or substances that the body uses in small amounts, as compared to macronutrients, which are the proteins, fats, and carbohydrates that make up all food. Vitamins are present in food, but adequate quantities of vitamins may be reduced when food is overcooked, processed, or improperly stored. For instance, processing whole wheat grain into white flour reduces the contents of vitamins B and E, fiber, and minerals, including zinc and iron. The body requires vitamins to support its basic biochemical functions, and deficiencies over time can lead to illness and disease.
Most vegetarians eat milk products and eggs, and as a group, these lacto-ovo-vegetarians enjoy good health. A healthful vegetarian diet falls within the food pyramid guidelines offered by the USDA. However, meat, fish and poultry are major sources of iron, zinc and B vitamins, so pay special attention to these nutrients. Vegans (those who eat only plant-based food) should consult a health care professional about adding vitamin and mineral supplements; make sure you consume sufficient quantities of protein, vitamin B12, vitamin D and calcium.
^ Jump up to: a b c Schwingshackl, L; Boeing, H; Stelmach-Mardas, M; Gottschald, M; Dietrich, S; Hoffmann, G; Chaimani, A (2017). "Dietary Supplements and Risk of Cause-Specific Death, Cardiovascular Disease, and Cancer: A Systematic Review and Meta-Analysis of Primary Prevention Trials". Advances in Nutrition: An International Review Journal. 8 (1): 27–39. doi:10.3945/an.116.013516. PMC 5227980. PMID 28096125.
Generally, nutrients from food sources are more efficiently utilized by the body than isolated substances. For instance, fresh fruit and vegetable juice could be used to provide concentrated amounts of particular nutrients, such as vitamins A and C, to the diet. As another example, eating plenty of leafy green vegetables is a healthy option for those wishing to add calcium to the diet.
The soil in areas with relatively low rainfall may in some cases contain an extremely high concentration of minerals, which is reflected in the plants growing there. This was well documented 70 years ago in the book Tomorrow's Food.  The Dentist George W. Heard found that the soil in Hereford, Texas, was exceptionally rich in minerals. Hereford became known as the "town without a toothache" after a newspaper article from January 29, 1942, reported that Hereford had the lowest incidence of tooth decay of any city in the United States.  Heard found that people in Hereford had exceptionally few dental cavities and also that the soil locally was especially rich in minerals. He emphasized that the population in the county ate unprocessed food and was drinking raw milk. 
It has not been scientifically established that large amounts of vitamins and minerals or dietary supplements help prevent or treat health problems or slow the aging process. Daily multivitamin tablets can be beneficial to some people who do not consume a balanced diet or a variety of foods. Generally, eating a well-balanced diet with a variety of foods provides the necessary nutrients your body needs. Eating whole foods is preferable to supplements because foods provide dietary fiber and other nutritional benefits that supplements do not. If you choose to take vitamin and mineral supplements, it is recommended to choose a multi-vitamin that does not exceed 100 percent of the Recommended Dietary Intake (RDI).
Consult your health care professional. Women of childbearing age may want to consider taking folic acid supplements to reduce the risk of having a pregnancy affected with neural tube defects. Many women and teenage girls don't get enough calcium or vitamin D, both of which are critical to healthy bones and avoiding osteoporosis. Some people with diabetes appear to benefit from chromium. Vegetarians, especially vegans, may want to consider supplements to obtain nutrients they aren't getting from animal products.
Among general reasons for the possible harmful effects of dietary supplements are: a) absorption in a short time, b) manufacturing quality and contamination, and c) enhancing both positive and negative effects at the same time. The incidence of liver injury from herbal and dietary supplements is about 16–20% of all supplement products causing injury, with the occurrence growing globally over the early 21st century. The most common liver injuries from weight loss and bodybuilding supplements involve hepatocellular damage with resulting jaundice, and the most common supplement ingredients attributed to these injuries are green tea catechins, anabolic steroids, and the herbal extract, aegeline. Weight loss supplements have also had adverse psychiatric effects.
Some fat is an important part of your diet; fat is part of every cell. It maintains skin and hair; stores and transports fat-soluble vitamins A, D, E and K; keeps you warm; and protects your internal organs. It even helps your mental processes—not surprising given that fat comprises about 60 percent of your brain. But many women consume too much fat. The American Heart Association (AHA) recommends that you keep your total fat intake between 25 and 35 percent of your total calories.
Cholesterol is a waxy, fat-like substance made by your body. It also is found in foods made from animals, like meat and dairy. Fruits and vegetables do not contain cholesterol. There are two types of cholesterol: HDL, or "good" cholesterol, and LDL, or "bad" cholesterol. Higher levels of total cholesterol and LDL or "bad" cholesterol raise your risk for heart disease. Almost half of American women have high or borderline high cholesterol.
Also limit the amount of cholesterol you consume. Cholesterol is a fat-like substance found in every cell of the body. It helps digest some fats, strengthen cell membranes and make hormones. But too much cholesterol can be dangerous: When blood cholesterol reaches high levels, it can build up on artery walls, increasing the risk of blood clots, heart attack and stroke. Although dietary cholesterol can contribute to heart disease, the greater risk comes from a diet high in saturated and trans fats.
Among other things, you need calcium to build healthy bones and teeth, keep them strong as you age, regulate the heart’s rhythm, and ensure your nervous system functions properly. Calcium deficiency can lead to, or exacerbate, mood problems such as irritability, anxiety, depression, and sleep difficulties. If you don’t get enough calcium in your diet, your body will take calcium from your bones to ensure normal cell function, which can lead to weakened bones or osteoporosis. Women are at a greater risk than men of developing osteoporosis, so it’s important to get plenty of calcium, in combination with magnesium and vitamin D, to support your bone health.
As the science of nutrition continually evolves, researchers recognize that nutrients needed to maintain a healthy lifestyle must be tailored to the individual for maximum effectiveness. Recognizing that people are not all alike and that one size does not fit all when it comes to planning and achieving a healthful diet, the Institute of Medicine's dietary guidelines, titled "Dietary Reference Intakes for Macronutrients," stress the importance of balancing diet with exercise and recommends total calories based on an individual's height, weight and gender for each of four different levels of physical activity.
Those who want to use natural healing methods, such as the use of food and supplements of essential nutrients to prevent or reverse illness, should consult therapists who are qualified to give advice on how natural therapies can help. I recommend that anyone interested in supplements read the references for this article as well as the archives of the Journal of Orthomolecular Medicine http://orthomolecular.org/library/jom/ and the Orthomolecular Medicine News Service http://orthomolecular.org/resources/omns/index.shtml . Both are free access online.
Keep a record of the supplements you take in one place, just as you should be doing for all of your medicines. Note the specific product name, the dose you take, how often you take it, and the reason why you use each one. You can also bring the products you use with you when you see your health care provider. The FDA provides a useful form, "My Medicine Record", to record the medicines and dietary supplements that you take. Share this form with your healthcare provider to discuss what's best for your overall health.
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. 
A dietary supplement is a manufactured product intended to supplement the diet when taken by mouth as a pill, capsule, tablet, or liquid. A supplement can provide nutrients either extracted from food sources or synthetic, individually or in combination, in order to increase the quantity of their consumption. The class of nutrient compounds includes vitamins, minerals, fiber, fatty acids and amino acids. Dietary supplements can also contain substances that have not been confirmed as being essential to life, but are marketed as having a beneficial biological effect, such as plant pigments or polyphenols. Animals can also be a source of supplement ingredients, as for example collagen from chickens or fish. These are also sold individually and in combination, and may be combined with nutrient ingredients. In the United States and Canada, dietary supplements are considered a subset of foods, and are regulated accordingly. The European Commission has also established harmonized rules to help insure that food supplements are safe and properly labeled. Among other countries, the definition of dietary supplements may vary as drugs or other classes of ingredients used in supplement products.
First, there is the sensation of eating the food. This includes what it tastes like (salty, sweet, umami, etc.), what it smells like, and how it feels in your mouth. This last quality — known as “orosensation” — can be particularly important. Food companies will spend millions of dollars to discover the most satisfying level of crunch in a potato chip. Food scientists will test for the perfect amount of fizzle in a soda. These elements all combine to create the sensation that your brain associates with a particular food or drink.
Eat in smaller plates. Science says that eating on a large plate tricks your brain into thinking that you haven’t eaten enough. Eat on a smaller plate to feel full quicker and avoid overeating. Moreover, the color of your plate could impact your food intake as well. According to a study conducted by Cornell University, people eat less when there is a higher color contrast between the plate and the food. If the color contrast between the two is lower, we tend to eat more. For instance, if you eat pasta with alfredo sauce on a white plate, you’ll probably eat more as compared to eating in, say, a blue plate.
Herbal supplements are added to the diet for both nutritional and medicinal purposes. Herbs have been used for centuries in many traditional medicine systems, and as sources of phytochemicals, or substances found in plants that have notable effects in the body. Chinese medicine and Ayurvedic medicine from India, two of the world's oldest healing systems, use hundreds of herbal medications. Naturopathy and homeopathy, two other systems of natural healing, also rely on herbal preparations as their main sources of medication. The medicinal effects of herbs are getting scientific validation; about one-fourth of all pharmaceuticals have been derived directly from plant sources, including aspirin (found in willow bark), codeine (from poppy seeds), paclitaxel (Taxol), a patented drug for ovarian and breast cancer (from the Pacific Yew tree), and many others.
Make the right changes. When cutting back on unhealthy foods in your diet, it’s important to replace them with healthy alternatives. Replacing dangerous trans fats with healthy fats (such as switching fried chicken for grilled salmon) will make a positive difference to your health. Switching animal fats for refined carbohydrates, though (such as switching your breakfast bacon for a donut), won’t lower your risk for heart disease or improve your mood.
When shopping for an herbal supplement, it's important to verify which parts of the plant were used in its production. Different components can produce different effects, some of which can harm your health. For example, research shows that while the roots of the herb kava seem to be safe, its stem peelings and leaves may contain compounds that could be toxic to the liver. Talking with your doctor or herbalist can help you determine which plant parts to look for.
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.