Healthy diet

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Leafy green, allium, and cruciferous vegetables are key components of a healthy diet.

A healthy diet is one that helps maintain or improve general health. It is thought to be important for lowering health risks, such as obesity, heart disease, diabetes, hypertension and cancer.[1] A healthy diet involves consuming primarily fruits, vegetables, and whole grains to satisfy caloric requirements, provides the body with essential nutrients, phytochemicals, and fiber, and includes adequate water consumption. A healthy diet supports energy needs and provides for human nutrition without exposure to toxicity or excessive weight gain from consuming excessive amounts.

Contents

Dietary recommendations

There are numerous diets and recommendations by medical and governmental institutions that promote health.

World Health Organization

The World Health Organization (WHO) makes the following 5 recommendations with respect to both populations and individuals:[2]

Other recommendations include:

American Heart Association / World Cancer Research Fund / American Institute for Cancer Research

The American Heart Association, World Cancer Research Fund, and American Institute for Cancer Research recommends a diet that consists mostly of unprocessed plant foods, with emphasis a wide range of whole grains, legumes, and non-starchy vegetables and fruits. This healthy diet is replete with a wide range of various non-starchy vegetables and fruits, that provide different colors including red, green, yellow, white, purple, and orange. They note that tomato cooked with oil, allium vegetables like garlic, and cruciferous vegetables like cauliflower, provide some protection against cancer. This healthy diet is low in energy density, which may protect against weight gain and associated diseases. Finally, limiting consumption of sugary drinks, limiting energy rich foods, including “fast foods” and red meat, and avoiding processed meats improves health and longevity. Overall, researchers and medical policy conclude that this healthy diet can reduce the risk of chronic disease and cancer.[4][5]

Harvard School of Public Health

The Nutrition Source of Harvard School of Public Health makes the following 10 recommendations for a healthy diet:[6]

Other than nutrition, the guide recommends frequent physical activity (exercise) and maintaining a healthy body weight.[6]

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.[12]

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,[13] 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.[14]

Obesity

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.[15] 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.[15] At two years, all calorie-reduced diet types cause equal weight loss irrespective of the macronutrients emphasized.[16]

Diet and possible reduced disease risk

There may be a relationship between lifestyle including food consumption and potentially lowering the risk of cancer or other chronic diseases. A healthy diet may consist mostly of whole plant foods, with limited consumption of energy-dense foods, red meat, alcoholic drinks and salt while reducing consumption of sugary drinks, and processed meat.[17] A healthy diet may contain non-starchy vegetables and fruits, including those with red, green, yellow, white, purple or orange pigments. Tomato cooked with oil, allium vegetables like garlic, and cruciferous vegetables like cauliflower may contain compounds which are under research for their possible anti-cancer activity.[4][5]

A healthy diet is low in energy density, lowering caloric content, thereby possibly inhibiting weight gain and lowering risk against chronic diseases.[4][5][18]

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.[19]

The WHO estimates that 2.7 million deaths are attributable to a diet low in fruit and vegetable every year.[19] 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.[20]

Fad diets

Fad diet usually refers to idiosyncratic diets and eating patterns. They are diets that claim to promote weight loss or treat obesity by various mechanisms,[21] provide little to no scientific reasoning behind their purported health benefits, and have little or no proof to support them.

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;[22][23] 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.[24]

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"[citation needed]. 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.[25] This may be due to tastes acquired in childhood and preferences for sugary, salty and/or fatty foods.[26]

See also

References

  1. ^ a b "WHO | Promoting fruit and vegetable consumption around the world". WHO. http://www.who.int/dietphysicalactivity/fruit/en/index.html.
  2. ^ "WHO | Diet". WHO. http://www.who.int/dietphysicalactivity/diet/en/index.html.
  3. ^ "WHO/FAO release independent Expert Report on diet and chronic disease". World Health Organization. http://www.who.int/mediacentre/news/releases/2003/pr20/en/. Retrieved 21 February 2011.
  4. ^ a b c "Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective". Washington DC: AICR, 2007. http://eprints.ucl.ac.uk/4841/1/4841.pdf.
  5. ^ a b c "American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention". Last Revised: 1/11/2012. http://www.cancer.org/acs/groups/cid/documents/webcontent/002577-pdf.pdf.
  6. ^ a b c d e f g "What Should I Eat?". The Nutrition Source. Harvard School of Public Health. http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/index.html. Retrieved 17 October 2012.
  7. ^ http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/carbohydrates/index.html
  8. ^ "The Bottom Line: Pay attention to the protein package. Fish, poultry, and beans are your best bets". http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein/index.html.
  9. ^ "The Bottom Line: Choose a fiber-filled diet, rich in whole grains, vegetables, and fruits". http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fiber/index.html.
  10. ^ "The Bottom Line: Calcium is important. But milk isn’t the only, or even best, source". http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/calcium-and-milk/index.html.
  11. ^ [http://www.hsph.harvard.edu/nutritionsource/healthy-drinks/healthy-drinks-full-story/index.html "The Nutrition Source Healthy Beverage Guidelines"]. http://www.hsph.harvard.edu/nutritionsource/healthy-drinks/healthy-drinks-full-story/index.html.
  12. ^ He FJ, MacGregor GA. Effect of longer-term modest salt reduction on blood pressure. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD004937. doi:10.1002/14651858.CD004937.
  13. ^ "Your Guide To Lowering Your Blood Pressure With DASH" (PDF). http://www.nhlbi.nih.gov/health/public/heart/hbp/dash/new_dash.pdf. Retrieved 2009-06-08.
  14. ^ Walker C, Reamy BV (April 2009). "Diets for cardiovascular disease prevention: what is the evidence?". Am Fam Physician 79 (7): 571–8. PMID 19378874.
  15. ^ a b Strychar I (January 2006). "Diet in the management of weight loss". CMAJ 174 (1): 56–63. doi:10.1503/cmaj.045037. PMC 1319349. PMID 16389240. http://www.cmaj.ca/cgi/content/full/174/1/56.
  16. ^ Sacks FM, Bray GA, Carey VJ, et al. (February 2009). "Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates". N. Engl. J. Med. 360 (9): 859–73. doi:10.1056/NEJMoa0804748. PMC 2763382. PMID 19246357. //www.ncbi.nlm.nih.gov/pmc/articles/PMC2763382/.
  17. ^ EXECUTIVE SUMMARY Policy and Action for Cancer Prevention Food, Nutrition, and Physical Activity. 2010. pp. 1. ISBN 978-0-9722522-5-6.
  18. ^ a b "WHO | Diet and physical activity: a public health priority". http://www.who.int/dietphysicalactivity/en/.
  19. ^ Lopez AD, Mathers CD, Ezzati M, Jamison DT, Murray CJ (May 2006). "Global and regional burden of disease and risk factors, 2001: systematic analysis of population health data". Lancet 367 (9524): 1747–57. doi:10.1016/S0140-6736(06)68770-9. PMID 16731270.
  20. ^ Katz DL (2003). "Pandemic obesity and the contagion of nutritional nonsense". Public Health Rev 31 (1): 33–44. PMID 14656042.
  21. ^ Mensink RP, Zock PL, Kester ADM, Katan MB (May 2003). "Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials". American Journal of Clinical Nutrition 77 (5): 1146–1155. ISSN 0002-9165. PMID 12716665. http://www.ajcn.org/content/77/5/1146.full?ijkey=846a72387ebc0d82545acd5442a0c3a9e9fc3566.
  22. ^ Thijssen, M.A. and R.P. Mensink. (2005). Fatty Acids and Atherosclerotic Risk. In Arnold von Eckardstein (Ed.) Atherosclerosis: Diet and Drugs. Springer. pp. 171–172. ISBN 978-3-540-22569-0.
  23. ^ Fernandez ML, Calle M (November 2010). "Revisiting dietary cholesterol recommendations: does the evidence support a limit of 300 mg/d?". Current Atherosclerosis Reports 12 (6): 377–383. http://www.springerlink.com/content/0ml5027045n1k473.
  24. ^ "Told to Eat Its Vegetables, America Orders Fries" article by Kim Severson in The New York Times September 24, 2010, accessed September 25, 2010
  25. ^ James WP (2008). "The fundamental drivers of the obesity epidemic". Obesity Research 9 Suppl 1 (Mar;9 Suppl 1:6-13): 6–13. doi:10.1111/j.1467-789X.2007.00432.x. PMID 18307693.

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