Healthy diet

File:Colorful Photo of Vegetables.png

Fresh vegetables are important components of a healthy diet.

Common culinary fruits. Bananas, apples, pears, strawberries, oranges, grapes, canary melons, water melon, cantaloupe, pineapple and mango.

A healthy diet is one that helps maintain or improve general health. It is important for lowering many chronic health risks, such as obesity, heart disease, diabetes, hypertension and cancer. A healthy diet involves consuming appropriate amounts of all essential nutrients and an adequate amount of water. Nutrients can be obtained from many different foods, so there are numerous diets that may be considered healthy. A healthy diet needs to have a balance of macro nutrients (fats, proteins, and carbohydrates), calories to support energy needs, and micro nutrients to meet the needs for human nutrition without inducing toxicity or excessive weight gain from consuming excessive amounts.

Dietary recommendations

Main article: List of nutrition guides

There are a number of diets and recommendations by numerous medical and governmental institutions that are designed to promote certain aspects of health.

World Health Organization

The World Health Organization (WHO) makes the following 5 recommendations with respect to both populations and individuals:

• Try to burn as much energy as you eat, and try to eat as much energy as you burn, as a healthy weight is a balance between those two.
• Increase consumption of food producing plants, particularly fruits, vegetables, legumes, whole grains and nuts
• Limit intake of fat and oil, and avoid saturated fats, which are those that become solid at room temperature such as coconut oil and all animal products including basically meat, dairy and egg. Prefer unsaturated fats, which remain liquid at room temperature instead, and which are found in almost all the plant based oils and foods. Eliminate trans-fatty acids
• Limit the intake of granulated sugar -- A 2003 report recommends less than 10% simple sugars
• Limit salt / sodium consumption from all sources and ensure that salt is iodized

Other recommendations include:

• Sufficient essential amino acids to provide cellular replenishment and transport proteins. All essential amino acids are present together only in animals. Many plants such as quinoa, soy, and hemp also provide almost all the essential acids but are always lacking in one or more essential amino acid. Those who omit meat products from their diets may still easily obtain all the essential amino acid in their diets by consuming adequate amounts of plant products and grain products, which combine to provide complete proteins to the diet. Fruits such as avocado and pumpkin seeds also have almost all of the essential amino acids.
• Essential micronutrients such as vitamins and certain minerals.
• Avoiding directly poisonous (e.g. heavy metals) and carcinogenic (e.g. benzene) substances;
• Avoiding foods contaminated by human pathogens (e.g. E. coli, tapeworm eggs).

American Heart Association

The American Heart Association recommends a diet rich in fruits, vegetables, healthful fatty acids and limited saturated fat.

For specific conditions

In addition to dietary recommendations for the general population, there are many specific diets that have primarily been developed to promote better health in specific population groups, such as people with high blood pressure (as in low sodium diets or the more specific DASH diet), or people who are overweight or obese (in weight control diets). However, some of them may have more or less evidence for beneficial effects in normal people as well.

Hypertension

A low sodium diet is beneficial for people with high blood pressure. A Cochrane review published in 2008 concluded that a long term (more than 4 weeks) low sodium diet in Caucasians has a useful effect to reduce blood pressure, both in people with hypertension and in people with normal blood pressure.

The DASH diet (Dietary Approaches to Stop Hypertension) is a diet promoted by the National Heart, Lung, and Blood Institute (part of the NIH, a United States government organization) to control hypertension. A major feature of the plan is limiting intake of sodium, and it also generally encourages the consumption of nuts, whole grains, fish, poultry, fruits and vegetables while lowering the consumption of red meats, sweets, and sugar. It is also "rich in potassium, magnesium, and calcium, as well as protein". Evidence shows that the Mediterranean diet improves cardiovascular outcomes.

Obesity

Further information: Dieting

Weight control diets aim to maintain a controlled weight. In most cases dieting is used in combination with physical exercise to lose weight in those who are overweight or obese.

Diets to promote weight loss are generally divided into four categories: low-fat, low-carbohydrate, low-calorie, and very low calorie. A meta-analysis of six randomized controlled trials found no difference between the main diet types (low calorie, low carbohydrate, and low fat), with a 2–4 kilogram weight loss in all studies. At two years, all calorie-reduced diet types cause equal weight loss irrespective of the macronutrients emphasized.

Cancer prevention

Further information: Diet and cancer

A comprehensive worldwide report, Food, Nutrition, Physical Activity and the Prevention of Cancer: a Global Perspective, compiled by World Cancer Research Fund and American Institute for Cancer Research, reports that there is significant relation between lifestyle (including food consumption) and cancer prevention. The same report recommends eating mostly foods of plant origin and aiming to meet nutritional needs through diet alone, while limiting consumption of energy-dense foods, red meat, alcoholic drinks and salt and avoiding sugary drinks, and processed meat.

Unhealthy diets

An unhealthy diet is a major risk factor for a number of chronic diseases including: high blood pressure, diabetes, abnormal blood lipids, overweight/obesity, cardiovascular diseases, and cancer.

The WHO estimates that 2.7 million deaths are attributable to a diet low in fruit and vegetable every year. Globally it is estimated to cause about 19% of gastrointestinal cancer, 31% of ischaemic heart disease, and 11% of strokes, thus making it one of the leading preventable causes of death worldwide.

Fad diets

Main article: Fad diet

Fad diet usually refer to idiosyncratic diets and eating patterns. They are diets that claim to promote weight loss or treat obesity by various mechanisms.

Public health

Fears of high cholesterol were frequently voiced up until the mid-1990s. However, more recent research has shown that the distinction between high- and low-density lipoprotein ('good' and 'bad' cholesterol, respectively) must be addressed when speaking of the potential ill effects of cholesterol. Different types of dietary fat have different effects on blood levels of cholesterol. For example, polyunsaturated fats tend to decrease both types of cholesterol; monounsaturated fats tend to lower LDL and raise HDL; saturated fats tend to either raise HDL, or raise both HDL and LDL; and trans fat tend to raise LDL and lower HDL. Dietary cholesterol itself is only found in animal products such as meat, eggs, and dairy, but studies have shown that even large amounts of dietary cholesterol only have negligible effects on blood cholesterol.

Particularly within the last five years government agencies have attempted to combat the amount and method of media coverage lavished upon "junk" foods. Governments also put pressure on businesses to promote healthful food options, consider limiting the availability of junk food in state-run schools, and tax foods that are high in fat. Vending machines in particular have come under fire as being avenues of entry into schools for junk food promoters. However, there is little in the way of regulation and it is difficult for most people to properly analyze the real merits of a company referring to itself as "healthy." Recently, the United Kingdom removed the rights for McDonald's to advertise its products, as the majority of the foods that were seen have low nutrient values and high fat counts were aimed at children under the guise of the "Happy Meal". The British Heart Foundation released its own government-funded advertisements, labeled "Food4Thought", which were targeted at children and adults displaying the gory nature of how fast food is generally constituted.

Cultural and psychological factors

From a psychological and cultural perspective, a healthier diet may be difficult to achieve for people with poor eating habits. This may be due to tastes acquired in childhood and preferences for sugary, salty and/or fatty foods.

See also

• List of diets

External links

• Diet, Nutrition and the prevention of chronic diseases, by a Joint WHO/FAO Expert consultation (2003)