• Healthy diet

• A healthy diet is one that helps maintain or improve health. It is important for the prevention of many chronic health risks such as: obesity, heart disease, diabetes, and cancer.^[1]

A healthy diet involves consuming appropriate amounts of all nutrients, and an adequate amount of water. Nutrients can be obtained from many different foods, so there are a wide variety of diets that may be considered healthy diets.

Dietary recommendations

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:^[2]

• Achieve an energy balance and a healthy weight
• Limit energy intake from total fats and shift fat consumption away from saturated fats to unsaturated fats and towards the elimination of trans-fatty acids
• Increase consumption of fruits and vegetables, legumes, whole grains and nuts
• Limit the intake of simple sugars
• Limit salt / sodium consumption from all sources and ensure that salt is iodized

Other recommendations include:

• Sufficient essential amino acids ("complete protein") to provide cellular replenishment and transport proteins. All essential amino acids are present in animals. A select few plants (such as soy and hemp) give all the essential acids. A combination of other plants may also provide all essential amino acids. Fruits such as avocado and pumpkin seeds also have all the essential amino acids.^[3][4]
• 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).

DASH diet

Main article: DASH diet

Composition

Main article: Human nutrition

A healthy diet needs to have a balance of macronutrients / energy ( fats, proteins, and carbohydrates ) and micronutrients to meet the needs of the individual without inducing toxicity from excessive amounts.

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.^[5]

The WHO estimates that 2.7 million deaths are attributable to a diet low in fruit and vegetable every year.^[5] Globally it is estimated to cause about 19% of gastrointestinal cancer, 31% of ischaemic heart disease, and 11% of strokes,^[1] thus making it one of the leading preventable causes of death worldwide.^[6]

Food additive controversy

Some^[who?] claim that food additives, such as artificial sweeteners, colorants, preserving agents, and flavorings may cause health problems such as increasing the risk of cancer or ADHD.^[7]

Fast food

Examples of fast food critics include Jamie Oliver, Morgan Spurlock and Eric Schlosser.

Fad diets

Main article: Fad diet

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^{[citation needed]}, 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.

Media coverage of mass-produced, processed, "snack" or "sweet" products directly marketed at children has worked to undermine policy efforts to improve eating habits. The main problem with such advertisements for foods is that alcohol and fast food are portrayed as offering excitement, escape and instant gratification.

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. Most 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 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 perspective, a new healthy diet may be difficult to achieve for a person with poor eating habits. This may be due to tastes acquired in early adolescence and preferences for fatty foods. It may be easier for such a person to transition to a healthy diet if treats such as chocolate are allowed; sweets may act as mood stabilizers, which could help reinforce correct nutrient intake.

It is known that the experiences we have in childhood relating to consumption of food affect our perspective on food consumption in later life. From this, we are able to determine ourselves our limits of how much we will eat, as well as foods we will not eat - which can develop into eating disorders, such as anorexia, bulimia, or orthorexia This is also true with how we perceive the sizes of the meals or amounts of food we consume daily; people have different interpretations of small and large meals based on upbringing.

While plants, vegetables, and fruits are known to help reduce the incidence of chronic disease,^{[citation needed]} the benefits on health posed by plant-based foods, as well as the percentage of which a diet needs to be plant based in order to have health benefits is unknown. Nevertheless, plant-based food diets in society and between nutritionist circles are linked to health and longevity, as well as contributing to lowering cholesterol, weight loss, and in some cases, stress reduction.^{[citation needed]}

Indeed, ideas of what counts as "healthy eating" have varied in different times and places, according to scientific advances in the field of nutrition, cultural fashions, religious proscriptions, or personal considerations.