Healthy eating

Healthy eating is the practice of making choices about what or how much one eats with the intention of improving or maintaining good health. Typically this means following recommendations of "experts" regarding a nutritional diet. The recommendations may address:

* total calorie consumption;
* balance of major nutrients (e.g., proteins, fats, carbohydrates);
* increased consumption of foods designated as beneficial;
* decreased consumption of foods designated as detrimental;
* increased consumption of specific vitamins or other micronutrients;
* avoidance of certain food additives (dyes, preservatives, sweeteners);
* avoidance of environmental food contaminants (e.g., mercury, pesticides, herbicides, aflatoxins)
* methods of food preparation (e.g., raw versus cooked).

The "experts" may be academically certified, or may be self-appointed. The evidence underlying their recommendations may be strong or weak by scientific standards. Our ideas of what counts as "healthy" have varied in different times and places, according to scientific advances in the field of nutrition, cultural fashions, religious proscriptions, or personal considerations.


Nutritional advice

Many governments and other organizations provide nutritional advice and launch schemes in order to promote healthy eating. Diets which lead to obesity (being severely overweight), diabetes, and other medical conditions, are a severe drain of resources for national health providers, and on businesses due to reduced productivity of staff. Moreover, personal well-being and overall happiness can be severely curtailed by a compromised diet.

A recent health campaign by the American government has attempted to impress the purported need to eat lots of fruit and vegetables using the slogan "5 a day". Adverts have given examples of what a portion of fruit or vegetables amounts to, and how 5 or more portions can be incorporated into one's diet.

Governments also put pressure on businesses to promote healthful food options, and regularly consider measures, such as banning the advertising of fast food, limiting the availablity of junk food in state-run schools, and taxing foods which are high in fat.

There is also near-unanimous agreement that hydrogenated fats (aka trans fats) are not a healthful form of food energy, and that consuming flaxseed oil or some types of fish and seafood (a source of omega-3 fatty acids) before meat and poultry may contribute to an individual's health and longevity. Unfortunately, consumption of predatory fish at the top of the food chain (such as swordfish, mackerel, shark, and albacore tuna) increases one's exposure to mercury and PCBs, so the hazards may outweigh the health benefits as most fish contains trace amounts of pollution. However, not all predatory fish swim in mercury/PCB-polluted waters (chiefly these are off the eastern seaboard of North America), so one need not neccessarily exclude the consumption of these fish.

Eggs have long been a source of controversy -- egg yolks are richer in cholesterol than egg whites, and should be consumed in moderation, whereas egg whites are almost pure protein and contain little or no substances suspected of causing obesity or heart disease.

Dairy products have had a shorter history of controversy, and charges levelled at dairy focus typically on one of three lines of reasoning. First, that the allegedly-poor conditions present on large-scale dairy farms may lead to sickened cows, which may lead to sickened (high pus) milk. Second, that milk is naturally meant to fatten baby cows into grown heifers in a few short years, and hence may be incompatible with a balanced human diet. Third, that healthy bone structures in humans require both calcium and magnesium. Milk and other dairy products are cited as being high in calcium, but lacking the magnesium levels required for strong bones. Such a deficiency would be mitigated by consuming other foods high in magnesium, such as nuts, seeds, green leafy vegetables, even certain mineral waters high in the element.

Carrots have also been proven to show improvements in many areas of health such as improved vision as well as lowering the risk of cancers caused by high cholesterol levels in the body. The main component of carrots responsible for improving vision is Beta carotene. This is also responsible for acting as an anti-oxidant which lowers free radicals, thus lowering the threat of cancer or heart attacks.

Research is being done on the effects of various chemicals - foods and nonfoods - on the mammal physiology. Such research is often funded by medical organizations, or pharmaceutical companies. Each study should be assessed in context: who was funding the research, and what the immediate goals were.

Fears of high cholesterol were frequently voiced up until the mid-1990s. However, more recent research has shown that the distiction between high- and low-density lipoprotein ('good' and 'bad' cholesterol, respectively) must be addressed when speaking of the potential ill effects of cholesterol. High density lipoprotein is often prevelent in animal products, such as bacon and egg yolks, whereas low density lipoprotein is more common in plant and fish tissues, such as olive oil and salmon.


Toxins

Almost all foods contain tiny amounts of toxins (natural poisonous substances), which normally do not pose a great danger to a healthy individual, due to low concentration. At higher toxin concentrations, a given food could simply not be considered a food. Some toxins may still have negative heath effects on susceptible people. For instance, many are allergic to some nuts, such as peanuts. The ingredient usually cited as being most critical to good health, water, has even been known to result in death when consumed excessively.


Food additives

Some people claim that food additives, such as artificial sweeteners, colorants, preserving agents, and flavourants may cause health problems even though they were extensively tested before being allowed on the market. For example, artificial colorants are claimed to cause hyperactivity in susceptible children. As another example, people on calorie restricted diets often choose to buy products advertised as "reduced calorie" or "no sugar added". These products contain artificial sweeteners. These are safe to consume in small quantities, and are of low toxicity. Safety studies may well show some advantage in substitutions, product by product. Over a period of time, many different products are approved for sale, each one relying on a study done in isolation, and each one suggesting the artificially sweetened product has fewer associated health problems than equivalent all-natural products. When dieters buy reduced-calorie soft drinks, biscuits, cakes, flavoured water, yogurt, and so on, all may contain combinations of the leading artificial sweeteners aspartame, acesulfame potassium or sucralose. Cumulative doses are at higher levels than those on which the safety studies were based.

The issue of sweetening is just one example. Other taste-enhancing additives (e.g. salt substitutes) or flavourants are also hidden in processed foods and drink, as are colourants. Mandatory food labelling is one attempt to overcome the problem. This invites the consumer to check the ingredients of their foods before consumption. However, the average person has no training in organic chemistry and its nutritional effects. Neither is it practical for individuals to manage score cards recording all the nutrients they consume.

Some would assert that research into the toxicity of many varied artificial ingredients has been inconclusive. The USA's Food and Drug Administration has very stringent requirements for the introduction of new food ingredients, and this includes rigorous testing on animals, where the animals are given exorbitant amounts of these chemicals - far more than humans ever would be likely to consume.