Healthy diet

Leafy green, cruciferous, and other raw vegetables may contribute to a healthy dietA healthy diet is a diet that helps to maintain or improve overall health. A healthy diet provides the body with essential nutrition: fluid, macronutrients, micronutrients, and adequate calories.^[1][2]For people who are healthy, a healthy diet is not complicated and contains mostly fruits, vegetables, and whole grains, and includes little to no processed food and sweetened beverages. The requirements for a healthy diet can be met from a variety of plant-based and animal-based foods, although a non-animal source of vitamin B12 is needed for those following a vegan diet.^[3] Various nutrition guidesare published by medical and governmental institutions to educate individuals on what they should be eating to be healthy. Nutrition facts labelsare also mandatory in some countries to allow consumers to choose between foods based on the components relevant to health.^[4]

A healthy lifestyle includes getting exercise every day along with eating a healthy diet. A healthy lifestyle may lower disease risks, such as obesity, heart disease, type 2 diabetes, hypertension and cancer.^[1][5]

There are specialized healthy diets, called medical nutrition therapy, for people with various diseases or conditions. There are also prescientific ideas about such specialized diets, 

World Health OrganizationEdit

The World Health Organization (WHO) makes the following 5 recommendations with respect to both populations and individuals:^[6]

1. Maintain a healthy weight by eating roughly the same number of calories that your body is using.
2. Limit intake of fats. Not more than 30% of the total calories should come from fats. Prefer unsaturated fats to saturated fats. Avoid trans fats.
3. Eat at least 400 grams of fruits and vegetables per day (potatoes, sweet potatoes, cassava and other starchy roots do not count). A healthy diet also contains legumes (e.g. lentils, beans), whole grainsand nuts.
4. Limit the intake of simple sugars to less than 10% of calorie (below 5% of calories or 25 grams may be even better).^[7]
5. Limit salt / sodium from all sources and ensure that salt is iodized. Less than 5 grams of salt per day can reduce the risk of cardiovascular disease.^[8]

WHO stated that insufficient vegetables and fruit is the cause of 2.8% of deaths worldwide.^[8]

Other WHO recommendations include:

• ensuring that the foods chosen have sufficient 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);
• and replacing saturated fats with polyunsaturated fats in the diet, which can reduce the risk of coronary artery disease and diabetes.^[8]

United States Department of AgricultureEdit

Main article: History of USDA nutrition guides

Main article: MyPlate

The Dietary Guidelines for Americans by the United States Department of Agriculture (USDA) recommends three healthy patterns of diet, summarized in table below, for a 2000 kcal diet.^[9]

It emphasizes both health and environmental sustainability and a flexible approach. The committee that drafted it wrote: "The major findings regarding sustainable diets were that a diet higher in plant-based foods, such as vegetables, fruits, whole grains, legumes, nuts, and seeds, and lower in calories and animal-based foods is more health promoting and is associated with less environmental impact than is the current U.S. diet. This pattern of eating can be achieved through a variety of dietary patterns, including the “Healthy U.S.-style Pattern”, the “Healthy Vegetarian Pattern" and the "Healthy Mediterranean-style Pattern".^[10] Food group amounts are per day, unless noted per week.

Food group/subgroup (units)	Healthy U.S. patterns	Healthy Vegetarianpatterns	Healthy Med-stylepatterns
Fruits (cup eq)	2	2	2.5
Vegetables (cup eq)	2.5	2.5	2.5
Dark green	1.5/wk	1.5/wk	1.5/wk
Red/orange	5.5/wk	5.5/wk	5.5/wk
Starchy	5/wk	5/wk	5/wk
Legumes	1.5/wk	3/wk	1.5/wk
Others	4/wk	4/wk	4/wk
Grains (oz eq)	6	6.5	6
Whole	3	3.5	3
Refined	3	3	3
Dairy (cup eq)	3	3	2
Protein Foods(oz eq)	5.5	3.5	6.5
Meat (red and processed)	12.5/wk	--	12.5/wk
Poultry	10.5/wk	--	10.5/wk
Seafood	8/wk	--	15/wk
Eggs	3/wk	3/wk	3/wk
Nuts/seeds	4/wk	7/wk	4/wk
Processed Soy (including tofu)	0.5/wk	8/wk	0.5/wk
Oils (grams)	27	27	27
Solid fats limit (grams)	18	21	17
Added sugarslimit (grams)	30	36	29

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

The American Heart Association, World Cancer Research Fund, and American Institute for Cancer Research recommend 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 full of 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.^[11][12]

In children, consuming less than 25 grams of added sugar (100 calories) is recommended per day.^[13]Other recommendations include no extra sugars in those under 2 years old and less than one soft drink per week.^[13] As of 2017, decreasing total fat is no longer recommended, but instead, the recommendation to lower risk of cardiovascular disease is to increase consumption of monounsaturated fats and polyunsaturated fats, while decreasing consumption of saturated fats.^[14]

Harvard School of Public HealthEdit

Further information: Healthy eating pyramid

The Nutrition Source of Harvard School of Public Health makes the following 10 recommendations for a healthy diet:^[15]

• Choose good carbohydrates: whole grains (the less processed the better), vegetables, fruits and beans. Avoid white bread, white rice, and the like as well as pastries, sugared sodas, and other highly processed food.^[16]
• Pay attention to the protein package: good choices include fish, poultry, nuts, and beans. Try to avoid red meat.^[17]
• Choose foods containing healthy fats. Plant oils, nuts, and fish are the best choices. Limit consumption of saturated fats, and avoid foods with trans fat.^[15]
• Choose a fiber-filled diet which includes whole grains, vegetables, and fruits.^[18]
• Eat more vegetables and fruits—the more colorful and varied, the better.^[15]
• Include adequate amounts of calcium in the diet; however, milk is not the best or only source. Good sources of calcium are collards, bok choy, fortified soy milk, baked beans, and supplements containing calcium and vitamin D.^[19]
• Prefer water over other beverages. Avoid sugary drinks, and limit intake of juices and milk. Coffee, tea, artificially-sweetened drinks, 100-percent fruit juices, low-fat milk and alcohol can fit into a healthy diet but are best consumed in moderation. Sports drinks are recommended only for people who exercise more than an hour at a stretch to replace substances lost in sweat.^[20]
• Limit salt intake. Choose more fresh foods, instead of processed ones.^[15]
• Drink alcohol in moderation. Doing so has health benefits, but is not recommended for everyone.^[15]
• Consider intake of daily multivitamin and extra vitamin D, as these have potential health benefits.^[15]

Other than nutrition, the guide recommends frequent physical exercise and maintaining a healthy body weight.^[15]

OthersEdit

David L. Katz, who reviewed the most prevalent popular diets in 2014, noted:

The weight of evidence strongly supports a theme of healthful eating while allowing for variations on that theme. A diet of minimally processed foods close to nature, predominantly plants, is decisively associated with health promotion and disease prevention and is consistent with the salient components of seemingly distinct dietary approaches. Efforts to improve public health through diet are forestalled not for want of knowledge about the optimal feeding of Homo sapiens but for distractions associated with exaggerated claims, and our failure to convert what we reliably know into what we routinely do. Knowledge in this case is not, as of yet, power; would that it were so.^[21]

Marion Nestle expresses the mainstream view among scientists who study nutrition:^[22]:10

The basic principles of good diets are so simple that I can summarize them in just ten words: eat less, move more, eat lots of fruits and vegetables. For additional clarification, a five-word modifier helps: go easy on junk foods. Follow these precepts and you will go a long way toward preventing the major diseases of our overfed society—coronary heart disease, certain cancers, diabetes, stroke, osteoporosis, and a host of others.... These precepts constitute the bottom line of what seem to be the far more complicated dietary recommendations of many health organizations and national and international governments—the forty-one “key recommendations” of the 2005 Dietary Guidelines, for example. ... Although you may feel as though advice about nutrition is constantly changing, the basic ideas behind my four precepts have not changed in half a century. And they leave plenty of room for enjoying the pleasures of food.^[23]:22

Reduced disease riskEdit

Further information: Diet and cancer

There may be a relationship between lifestyle including food consumption and potentially lowering the risk of cancer or other chronic diseases. A diet high in fruits and vegetables appears to decrease the risk of cardiovascular disease and death but not cancer.^[34]

Eating a healthy diet and getting enough exercise can maintain body weight in normal ranges and prevent obesity in most people, and can thus prevent the chronic diseases and poor outcomes associated with obesity.^[