Sugar substitute
A  sugar substitute is a food additive that duplicates the effect of sugar or corn syrup in taste, but usually has less food energy.  Some sugar substitutes are natural and some are synthetic.  Those that are not natural are, in general, referred to as artificial sweeteners.
An important class of sugar substitutes are known as high-intensity sweeteners. These are compounds with sweetness that is many times that of sucrose, common table sugar.  As a result, much less sweetener is required, and energy contribution often negligible. The sensation of sweetness caused by these compounds (the "sweetness profile") is sometimes notably different from sucrose, so they are often used in complex mixtures that achieve the most natural sweet sensation.
If the sucrose (or other sugar) replaced has contributed to the texture of the product, then a bulking agent is often also needed. This may be seen in soft drinks labeled as "diet" or "light," which contain artificial sweeteners and often have notably different mouthfeel, or in table sugar replacements that mix maltodextrins with an intense sweetener to achieve satisfactory texture sensation.
In the United States, five intensely-sweet sugar substitutes have been approved for use. They are saccharin, aspartame, sucralose, neotame, and acesulfame potassium. There is some ongoing controversy over whether artificial sweeteners are health risks. This controversy is fueled by anecdotal reports and sometimes poorly-controlled studies that have gained publicity via the internet and popular press. Scientifically-controlled peer-reviewed studies have consistently failed to produce evidence of adverse effects caused by consumption of these products.  There is also a herbal supplement, stevia, used as a sweetener.  Controversy surrounds stevia's safety and there is a battle over its approval as a sugar substitute.
The majority of sugar substitutes approved for food use are artificially-synthesized compounds. However, some bulk natural sugar substitutes are known, including sorbitol and xylitol, which are found in berries, fruit, vegetables, and mushrooms. It is not commercially viable to  extract these products from fruits and vegetables, so they  are produced by catalytic hydrogenation of the appropriate reducing sugar.  For example, xylose is converted to xylitol, lactose to lactitol, and glucose to sorbitol. Still other natural substitutes are known, but are yet to gain official approval for food use.
Some non-sugar sweeteners are polyols, also known as "sugar alcohols."  These are, in general, less sweet than sucrose, but have similar bulk properties and can be used in a wide range of food products. Sometimes the sweetness profile is 'fine-tuned' by mixing high-intensity sweeteners. As with all food products, the development of a formulation to replace sucrose is a complex proprietary process.

# Food industry usage of artificial sweeteners
The food and beverage industry is increasingly replacing sugar or corn syrup with artificial sweeteners in a range of products traditionally containing sugar. In the UK, for instance, it is now almost impossible to find any non-cola soft drinks in supermarkets that are not flavored with artificial sweeteners, and even things like pickled beetroots and gherkins are increasingly artificially sweetened.
Artificial sweeteners cost the food industry only a fraction of the cost of natural sweeteners in spite of the extremely high profit margins for manufacturers of artificial sweeteners. So it is not surprising that the food industry is promoting its "diet" or "light" products heavily, thus moving the customers over to its even more profitable artificially-sweetened products.
According to market analysts Mintel, a total of 3,920 products containing artificial sweeteners were launched in the US between 2000 and 2005. In 2004 alone, 1,649 artificially-sweetened products were launched. According to market analysts Freedonia, the US artificial sweetener market is set to grow at around 8.3% per year to $189 million in 2008.
Aspartame is currently the most popular sweetener in the US food industry, as the price has dropped significantly since the Monsanto patent expired in 1992. However, sucralose may soon replace it, as alternative processes to Tate & Lyle's patent seem to be emerging. According to Morgan Stanley, this can mean that the price of sucralose will drop by 30%.

# Reasons for use
There are four main reasons why individuals use a sugar substitute:
- To assist in weight loss; some people choose to limit their food energy intake by replacing high-energy sugar or corn syrup with other sweeteners having little or no food energy. This allows them to eat the same foods they normally would, while allowing them to lose weight and avoid other problems associated with excessive caloric intake.
However, one study by the University of Texas Health Science Center at San Antonio showed that, rather than promoting weight loss, the use of diet drinks was a marker for increasing weight gain and obesity. Those that consumed diet soda were more likely to gain weight than those that consumed naturally-sweetened soda. Sharon P. Fowler, MPH, who conducted the study, posited that it is not the diet drinks but something associated with their use that is linked to weight gain, perhaps simply that use of diet drinks increased as a person noticed that he or she was gaining weight. Fowler also speculated that perhaps giving the body the "taste" of energy-rich foods triggers a search for the real thing, or, as nutrition expert Leslie Bonci, MPH, RD, put it, "People think they can just fool the body. But maybe the body isn't fooled. If you are not giving your body that food energy you promised it, maybe your body will retaliate by wanting more energy."
- Dental care  sugar substitutes are toothfriendly, as they are not fermented by the microflora of the dental plaque.
- Diabetes mellitus  people with diabetes have difficulty regulating their blood sugar levels. By limiting their sugar intake with artificial sweeteners, they can enjoy a varied diet while closely controlling their sugar intake. Also, some sugar substitutes do release energy, but are metabolized more slowly, allowing blood sugar levels to remain more stable over time.
- Reactive hypoglycemia  individuals with reactive hypoglycemia will produce an excess of insulin after quickly absorbing glucose into the bloodstream.  This causes their blood glucose levels to fall below the amount needed for proper body and brain function.  As a result, like diabetics, they must avoid intake of high-glycemic foods like white bread, and often choose artificial sweeteners as an alternative.
- Avoiding processed foods  individuals may opt to substitute refined white sugar with less-processed sugars such as fruit juice or maple syrup. (See List of unrefined sweeteners).

# Sugar substitute health controversies
There is ongoing controversy over the supposed health risks of artificial sweeteners such as saccharin and aspartame. Some studies have shown that aspartame causes brain tumors as well as lymphatic cancers in laboratory animals, and suggest that saccharin causes bladder cancer in lab animals - but this is unlikely to affect humans, since the mechanism that is believed to cause saccharin to be a carcinogen to mice does not exist in humans. The U.S. Food and Drug Administration (FDA) determined in 1981 that aspartame is safe to use in foods, but only after it had been denied for many years. It has also ruled that all products containing aspartame must include a warning to phenylketonurics that the sweetener contains phenylalanine (as do many foods).

## Cyclamate controversy
In the United States, the FDA banned the sale of cyclamate in 1970 after lab tests in rats involving a 10:1 mixture of cyclamate and saccharin indicated that large amounts of cyclamates causes bladder cancer, a disease to which rats are particularly susceptible. The findings of these studies have been challenged and some companies are petitioning to have cyclamates reapproved. Cyclamates are still used as sweeteners in many parts of the world, and are used with official approval in over 55 countries.

## Saccharin controversy
Saccharin was the first artificial sweetener and was originally synthesized in 1879 by Remsen and Fahlberg.  Its sweet taste was discovered by accident. It had been created in an experiment with toluene derivatives. A process for the creation of saccharin from phthalic anhydride was developed in 1950, and, currently, saccharin is created by this process as well as the original process by which it was discovered. It is 300 to 500 times as sweet as sugar (sucrose) and is often used to improve the taste of toothpastes, dietary foods, and dietary beverages. The bitter aftertaste of saccharin is often minimized by blending it with other sweeteners.
Fear about saccharin increased when a 1960 study showed that high levels of saccharin may cause bladder cancer in laboratory rats. In 1977, Canada banned saccharin due to the animal research. In the United States, the FDA considered banning saccharin in 1977, but Congress stepped in and placed a moratorium on such a ban. The moratorium required a warning label and also mandated further study of saccharin safety.
Subsequently, it was discovered that saccharin causes cancer in male rats by a mechanism not found in humans. At high doses, saccharin causes a precipitate to form in rat urine. This precipitate damages the cells lining the bladder ("urinary bladder urothelial cytotoxicity") and a tumor forms when the cells regenerate ("regenerative hyperplasia"). According to the International Agency for Research on Cancer, part of the World Health Organization, "Saccharin and its salts was downgraded from Group 2B, possibly carcinogenic to humans, to Group 3, not classifiable as to carcinogenicity to humans, despite sufficient evidence of carcinogenicity to animals, because it is carcinogenic by a non-DNA-reactive mechanism that is not relevant to humans because of critical interspecies differences in urine composition."
In 2001, the United States repealed the warning label requirement, while the threat of an FDA ban had already been lifted in 1991. Most other countries also permit saccharin but restrict the levels of use, while other countries have outright banned it.

## Aspartame controversy
Aspartame was discovered in 1965 by James M. Schlatter at the G.D. Searle company (later purchased by Monsanto).  He was working on an anti-ulcer drug and spilled some aspartame on his hand by accident. When he licked his finger, he noticed that it had a sweet taste. It is an odorless, white crystalline powder that is derived from the two amino acids aspartic acid and phenylalanine. It is about 200 times as sweet as sugar and can be used as a tabletop sweetener or in frozen desserts, gelatins, beverages, and chewing gum. Its chemical name is L-alpha-aspartyl-L-phenylalanine methyl ester and its chemical formula is C14H18N2O5.  Though it has no bitter aftertaste as does saccharin, its drawback is that it might not taste exactly like sugar because it reacts with other food flavors. When eaten, aspartame is metabolized into its original
amino acids and has a relatively low food energy.
Initial safety testing suggested that aspartame caused brain tumors in rats; as a result, the additive was held up in the United States for many years in the FDA's approval process. In 1980, the FDA convened a Public Board of Inquiry (PBOI) consisting of independent advisors charged with examining the purported relationship between aspartame and brain cancer. The PBOI's conclusions were unclear as to whether aspartame causes brain damage, and recommended against approving aspartame at that time, citing unanswered questions about cancer in laboratory rats. In 1981, FDA Commissioner Arthur Hull Hayes, newly appointed by President Ronald Reagan, approved aspartame as a food additive.  He was closely associated with the artificial sweetener industry, having several close friends, most notably Donald Rumsfeld, former United States Secretary of Defense, and then the CEO of G.D. Searle.  Hayes cited data from a single Japanese study that had not been available to the members of the PBOI, as his reason for approval.
Since the FDA approved aspartame for consumption, some researchers have suggested that a rise in brain tumor rates in the United States may be at least partially related to the increasing availability and consumption of aspartame. Some research, often supported by companies producing artificial sweeteners, has failed to find any link between aspartame and cancer or other health problems. A recent research showed a clear link between this substance and cancer; a link that may be sufficient evidence for the FDA to pull aspartame from the market. This research has led the Center for Science in the Public Interest to classify aspartame as a substance to be avoided in its Chemical Cuisine Directory. However, the EFSA's press release about the study, published on 5 May 2006, concluded that the increased incidence of lymphomas/leukaemias reported in treated rats was unrelated to aspartame, the kidney tumors found at high doses of aspartame were not relevant to humans, and that based on all available scientific evidence to date, there was no reason to revise the previously established Acceptable Daily Intake levels for aspartame.

## Sucralose controversy
Sucralose is a chlorinated sugar that is about 600 times as sweet as sugar. It is produced from sucrose when three chlorine atoms replace three hydroxyl groups. It is used in beverages, frozen desserts, chewing gum, baked goods, and other foods. Unlike other artificial sweeteners, it is stable when heated and can therefore be used in baked and fried goods. Sucralose is minimally absorbed by the body and most of it passes out of the body unchanged. The FDA approved sucralose in 1998.
Sucralose belongs to a class of chemicals called organochlorides, some types of which are highly toxic or carcinogenic; however, the presence of chlorine in an organic compound does not in any way ensure toxicity. The way sucralose is metabolized may suggest a reduced risk of toxicity. For example, sucralose is extremely insoluble in fat and thus does not accumulate in fat as do some other organochlorides; sucralose also does not break down or dechlorinate.
Most of the controversy surrounding Splenda, a sucralose sweetener, is focused not on safety, but on its marketing. It has been marketed with the slogan, "Splenda is made from sugar, so it tastes like sugar." Sucralose is a chlorinated sugar, it is based on either raffinose, a carbohydrate containing three different kinds of sugar molecules, or sucrose. With either base sugar, processing replaces three oxygen-hydrogen groups in the sugar molecule with three chlorine atoms.
The "Truth About Splenda" website was created in 2005 by The Sugar Association, an organization representing sugar beet and sugar cane farmers in the United States, in order to provide an alternate view of sucralose compared to its manufacturer's marketing. In December of 2004, five separate false-advertising claims were filed against Splenda manufacturers Mersiant and McNeil Nutritionals for claims made about Splenda. French courts ordered the slogan to no longer be used in France, while in the U.S. the case came to an undisclosed settlement during the trial.

## Lead acetate
Lead acetate (sometimes called sugar of lead) is an artificial sugar substitute made from lead that is of historical interest because of its widespread use in the past, such as by ancient Romans. The use of lead acetate as a sweetener eventually produced lead poisoning in any individual ingesting it habitually.  Lead acetate was abandoned as a food additive throughout most of the world after the high toxicity of lead compounds became apparent.

# List of sugar substitutes
The three primary compounds used as sugar substitutes in the United States are saccharin (e.g., Sweet'N Low), aspartame (e.g., Equal, NutraSweet) and sucralose (e.g., Splenda, Altern). In many other countries cyclamate and the herbal sweetener stevia are used extensively.

## Natural sugar substitutes
- Brazzein  Protein, 800 sweetness of sucrose (by weight)
- Curculin  Protein, 550 sweetness (by weight)
- Erythritol  0.7 sweetness (by weight), 14 sweetness of sucrose (by food energy), 0.05 energy density of sucrose
- Fructose  1.7 sweetness (by weight and food energy), 1.0 energy density of sucrose
- Glycyrrhizin  50 sweetness (by weight)
- Glycerol  0.6 sweetness (by weight), 0.55 sweetness (by food energy), 1.075 energy density, E422
- Hydrogenated starch hydrolysates  0.40.9 sweetness (by weight), 0.51.2 sweetness (by food energy), 0.75 energy density
- Lactitol  0.4 sweetness (by weight), 0.8 sweetness (by food energy), 0.5 energy density, E966
- Lo Han Guo - 300 sweetness (by weight)
- Mabinlin  Protein, 100 sweetness (by weight)
- Maltitol  0.9 sweetness (by weight), 1.7 sweetness (by food energy), 0.525 energy density, E965
- Maltooligosaccharide
- Mannitol  0.5 sweetness (by weight), 1.2 sweetness (by food energy), 0.4 energy density, E421
- Miraculin  Protein, does not taste sweet by itself, but modifies taste receptors to make sour things taste sweet temporarily
- Monellin  Protein, 3,000 sweetness (by weight)
- Pentadin  Protein, 500 sweetness (by weight)
- Sorbitol  0.6 sweetness (by weight), 0.9 sweetness (by food energy), 0.65 energy density, E420
- Stevia  250 sweetness (by weight)
- Tagatose  0.92 sweetness (by weight), 2.4 sweetness (by food energy), 0.38 energy density
- Thaumatin  Protein, 2,000 sweetness (by weight), E957
- Xylitol  1.0 sweetness (by weight), 1.7 sweetness (by food energy), 0.6 energy density, E967

## Artificial sugar substitutes
Note that because many of these have little or no food energy, comparison of sweetness based on energy content is not meaningful.
- Acesulfame potassium  200 sweetness (by weight), Nutrinova, E950, FDA Approved 1988
- Alitame  2,000 sweetness (by weight), Pfizer, Pending FDA Approval
- Aspartame  160200 sweetness (by weight), NutraSweet, E951, FDA Approved 1981
- Salt of aspartame-acesulfame  350 sweetness (by weight), Twinsweet, E962
- Cyclamate  30 sweetness (by weight), Abbott, E952, FDA Banned 1969, pending re-approval
- Dulcin  250 sweetness (by weight), FDA Banned 1950
- Glucin  300 sweetness (by weight)
- Neohesperidin dihydrochalcone  1,500 sweetness (by weight), E959
- Neotame  8,000 sweetness (by weight), NutraSweet, FDA Approved 2002
- P-4000  4,000 sweetness (by weight), FDA Banned 1950
- Saccharin  300 sweetness (by weight), E954, FDA Approved 1958
- Sucralose  600 sweetness (by weight), Splenda, Tate & Lyle, E955, FDA Approved 1998
- Isomalt  0.450.65 sweetness (by weight), 0.91.3 sweetness (by food energy), 0.5 energy density, E953