Rarely does the opportunity to improve the health of the nation collide with a strong potential for profits in the food and beverage industry. The growing low-carbohydrate food and beverage sector offers just that sort of rare opportunity.

The buzzword for 2004 is "low-carb" with everyone from dieters to doctors, researchers to ranchers, hoping to benefit from this nutritional approach. The main goal of this dietary mindset is to reduce carbohydrate intake to lose weight, control type-2 diabetes or related disorders, and to improve the ratios of the cholesterol-carrying particles in the blood.

Expanding markets
Low-carb diets are not only affecting waistlines, but also bottom lines across the food and beverage industry. Some sectors saw sharp declines as carbohydrate-conscious consumers shunned bread, pasta, potatoes and baked goods. In contrast, low-carb consumers fueled record sales for eggs, bacon, cheese, pork, poultry and beef. Throughout the year, companies like Atkins Nutritionals, Keto Foods, CarbSense, and Carbolite introduced an average of two new low-carb products a day according to ProductScan Online. In addition to the retail activities, chain restaurants, such as Subway, Burger King, Blimpies and T.G.I. Friday's are adding low-carb selections to their menus. McDonald's has begun to offer data on carbohydrate content of their foods in the New York City area and tell customers how to modify items on the existing menu to reduce their carbohydrate intake.

In the past year, companies in the low-carb niche have ventured beyond the Internet, nutrition-oriented centers and mom and-pop stores into the vast aisles of American retailers. In doing so, they are now finding themselves up against classic established brands made by food giants like Kraft, ConAgra, and Nestle. These major companies are still creating their long-term strategies for low-carb: Do they try to formulate products or simply gobble up existing companies?

To date, the big players are just beginning to make a little noise in this sector, with only a few established brands offering low-carb products. Nevertheless, billions of dollars are on the line in the long-term, and it is clear that the smart money is getting into this game. Even the largest American retailer, Wal-Mart, is rumored to have a low-carb private-label brand ready to launch sometime this year.

The low-carb niche companies presently enjoy a small competitive advantage due to years of virtually no competition from the major brands. This has allowed them to grow as low-carb eating has gained in popularity. However, as low-carb continues to move to the mainstream, the established companies can quickly regain competitiveness if they understand consumer desires and the science backing the movement. Food producers must understand that this shift in food consumption is not a fad, but a true paradigm shift in nutritional thinking.

Understanding low-carb diets
In the media, low-carb is often used interchangeably with "Atkins" even though over two-dozen different low-carbohydrate eating plans are popular among consumers. These programs differ in how many carbohydrates one eats each day and how one tracks carbohydrates, fat or calories.

The Atkins' Diet is the most carbohydrate-restrictive. It limits carbohydrate intake to just 20 grams (after deducting fiber) each day for the first two weeks, and then encourages dieters to reintroduce carbohydrates slowly as they continue to lose weight. The plan includes four phases -- Induction, Ongoing Weight Loss, Pre-Maintenance and Lifetime Maintenance -- with the average dieter reaching 75 to 125 grams of carbohydrates per day in Lifetime Maintenance when they reach their goal weight.

While the media is quick to portray the plan as "all the meat, eggs, butter and bacon you want," the reality is that, from day one, Atkins also recommends high consumption of vegetables. Dieters are required to consume at least 3 cups of nonstarchy vegetables and salads each day. When followed correctly, the plan, from Induction to Maintenance, usually meets or surpasses the RDA for most nutrients. By the Lifetime Maintenance phase, a dieter may include selections from all of the traditional "food groups." Indeed, long-term devotees are allowed brown rice, whole-wheat pasta, sweet potatoes and an assortment of low-carb processed foods.

The Zone, at the other end of the spectrum, is by far the most carbohydrate-lenient. It encourages carbohydrate, fat and protein intake based on percentaage of calories eaten each day in a ratio of 40:30:30 (respectively). By following this formula, the Zone promotes reduced consumption of carbohydrate while limiting intake of fat to the recommended 30% limit in the current U.S. Dietary Guidelines. Zone dieters are encouraged to select complex carbohydrates and shun refined carbohydrates in the short- and long-term.

Between Atkins and the Zone are another dozen or so low-carb diets -- Sugar Busters, Carbohydrate Addict's, No-Grain Diet, Paleo Diet, Neaderthin, GO Diet, Protein Power, Sommersize, South Beach -- each with slightly different recommendations for carbohydrate consumption, weight-loss and maintenance. Interestingly, regardless of how many carbohydrates any plan recommends, they all have one common denominator -- the elimination or severe restriction of sugars, starches and refined-grain products. Aside from the fairly minor differences in carbohydrate intake, the plans differ only in the amount and type of protein encouraged and the amount and type of fat one includes each day.

Despite the fact that the scientific evidence behind low-carb nutrition is sound and compelling, it still has detractors. Irregardless of the intensity of the debate between low-carb supporters and detractors, however, both sides agree on one major point -- the typical American diet is overloaded with simple carbohydrates like white flour, white rice, and added sugars, such as high-fructose corn syrup. For the food and beverage industry, the challenge is to develop products that are suitable across the different low-carb plans, offer comparable taste and texture of their high-carb cousins, and appeal to consumers not yet convinced that eating low-carb is healthy.

Herein lies the biggest opportunity for the food industry -- the development of foods that use fewer simple carbohydrates in general, and to offer tempting low-carb selections to those that desire them.

Given what we now know about the roles of fat, protein and carbohydrates in the diet, tremendous opportunities now exist to create food products that will enjoy increased value and competitiveness in the marketplace. Although whole foods in their natural states are undoubtedly the preferred sources for human nutrients, our modern world provides numerous instances where we consume designed or modified foodstuffs. The information below will help manufacturers exploit these opportunities.

The low-carb consumer
Before addressing the particulars of lipid, protein and carbohydrate ingredients, food designers need to understand two basic facts about the low-carbohydrate food consumer.

First, these individuals tend to eat very few sweets. They often develop a sensitivity to sweetness and find themselves completely satisfied with less-sweet foods. From a taste standpoint, they often reject highly sugared foods, such as breakfast cereals and sodas. In fact, foods not usually considered sweets, such as white bread, begin to taste sweet.

Second, in the majority of low-carb plans, total fat content is generally not an issue, except for "unhealthy" fats such as trans-fats, of course. Low-carbohydrate consumers expect products with an excellent mouthfeel and items that generate satiety and a "stick to the ribs" sensation after eating. With this in mind, food designers can use this information to design successful food products.

Low-carb consumers typically are looking for fats and protein in higher levels that a typical diet, and lower carbohydrate levels. But the specific ingredients used also impact selection.

Learning about lipids
Because people are adopting these eating patterns to promote health, choosing the right fats is on the top of the list. The scientific community still faces a great deal of debate on which fats and fatty acids are "good" versus "bad." But over the last several years, one issue has become clear: Trans fats (i.e. partially hydrogenated shortenings and oils) have been definitively linked to a growing number of degenerative diseases, and the food industry has been taking steps to minimize them or phase them completely out of food products intended for human consumption. They have no beneficial role in nutrition, a position supported by the Institute of Medicine/National Academies of Science (IOM/NAS) report on macronutrients that recommends "trans-fatty-acid consumption be as low as possible while consuming a nutritionally adequate diet."

Hydrogenation adds hydrogen atoms to unsaturated sites on fatty acids, which eliminates double bonds. This solidifies the fats and increases their shelf life and flavor stability by eliminating double bonds, which protects them against oxidative rancidity. Ruminants, such as cattle, also produce a small amount of trans fat in their gastrointestinal tract, so low levels of trans isomers are found in dairy and beef fat. Partial hydrogenation allows some double bonds to remain, but also alters their configuration from cis to trans. Numerous studies have found that trans-fat intake raises the LDL ("bad") cholesterol in the blood and decreases HDL-C (the "good" cholesterol), which increases the risk of developing coronary heart disease (CHD). In addition to increasing the LDL/HDL cholesterol ratio, trans fatty acids increase Lipoprotein-A (another risk factor for CHD) when substituted for saturated fat. The FDA will require that the amount of trans fat in a serving be listed on a separate line under saturated fat on the Nutrition Facts panel on all foods by Jan. 1, 2006.

The one exception to this rule is alpha-rumenic acid (a.k.a. conjugated linoleic acid [CLA], or 9-cis, 11-trans C 18:1), a naturally-occurring fatty acid found at concentrations generally less than 2% in the meat of ruminant animals. For regulatory purposes, FDA has defined trans fatty acids as all unsaturated fatty acids that contain one or more isolated (i.e., nonconjugated) double bonds in a trans configuration, so CLA would be excluded from the definition of trans fat.

The IOM/NAS has made similar recommendations regarding saturated fat and cholesterol consumption -- reduced consumption because of a negative effect on cholesterol levels. The belief is that saturated fats increase LDL cholesterol to a similar, or even lower, degree as trans fat, but without the undesirable decrease in HDL cholesterol. What's more, specific saturated fatty acids appear to have different effects -- stearic is believed to have a neutral effect on blood lipids. In addition, traditional diet recommendations limit fat consumption to not more that 30% of calories.

However, many, especially in the low-carb camp, are questioning this heretofore "conventional wisdom." For the statistically minded: It appears likely that trans-fats have been a confounding variable in the scientific studies that have purportedly found a link between fat intake and disease. (A confounder is a statistical term that describes a variable that is linked to both the exposure and the outcome of a question of interest.) The interested reader will find that virtually all published studies over the past 30 years have failed to control for this confounding variable; hence are essentially invalid.

Taking this into consideration, food designers now have virtually unfettered options when it comes to the design of products that contain natural lipids. This applies to naturally occurring amounts of dietary cholesterol as well. They can and should exploit all the beneficial taste attributes of various lipid sources. Butter and olive oil, for example, can be used ad libitum.

Product designers should go to thoughtful lengths to include lipids that have well-defined health benefits and promote their inclusion in the products' contents. Conjugated linoleic acids, omega-3 oils, and unhydrogenated oils can be promoted for their known benefits on cardiovascular disease, high blood pressure, etc. Saturated oils, such as palm and coconut can be promoted for their well-known thermogenic (i.e. heat-producing) effects on metabolism. (People living in arctic conditions have exploited this fact for centuries.) High-fat diets are known to increase nitrogen retention (i.e. maintenance of muscle mass) and manufacturers can promote this fact when a product also contains protein.

Designers can also take advantage of the dual benefits of fat-soluble antioxidants. The tocopherols (vitamin E), carotenes (vitamin A precursors), and co-enzyme Q are all beneficial nutrients that can also satisfy some of the preservative needs of lipid-containing food products. In addition, the lipid content of the food promotes the vitamin absorption and bioavailability of fat-soluble vitamins consumed from other sources in the diet.

Protein's possibilities  
The health benefits of protein cannot be overstated. In addition to being an essential nutrient for life, protein has a number of specific benefits desired by the carbohydrate-conscious consumer. Protein increases calcium absorption from the gut and preserves muscle and bone mass when one is dieting to lose weight. Protein promotes growth hormone release, which fosters lipolysis (fat burning) and the preservation of lean body mass. Protein creates significantly more heat during metabolism than comparable amounts of carbohydrate. Furthermore, in people with normal kidney and liver function, generous amounts of dietary protein have never been shown to be harmful. This is just a short list of protein-specific benefits.

Protein content clearly adds value to any product aimed at the general or low-carb-specific market. Items that contain the nine essential and two semi-essential, or conditionally essential, amino acids can claim the most nutritional value. The nine essential amino acids in human nutrition are: leucine, histidine, isoleucine, valine, threonine, methionine, phenylalanine, tryptophan and lysine. Conditionally essential amino acids include cystine and tyrosine.

Various powdered protein formulations share similar physical characteristics with grain flours. Depending on the product and the function of the flour, a significant proportion of a flour-containing recipe can be substituted with a soy protein powder, for example. This adaptation to a higher protein product can be made quickly and with little capital outlay in some cases.

There is some controversy regarding the best sources of dietary protein. There is general consensus that animal sources most closely contain the amino acid proportions required in human nutrition. Protein quality can be expressed by using the protein efficiency ratio (PER) or the protein digestibility corrected amino acid score (PDCAAS). Egg whites have been the historical gold standard; their score of 1.0 is optimal. PDCAAS has now been adopted as the official method by the World Health Organization, the USFDA and the US Department of Agriculture. PDCAAS determines protein quality based on the amino acid requirements of a 2- to 5-year-old child (the age group with the highest demand), adjusted for digestibility. Proteins can have different PERs -- in some cases, exceeding 1.0 -- while still having a PDCAAS of 1.0, however. For the most part, egg, dairy and soy proteins have scores equal or close to 1.0.

Egg protein can be more costly, but generally is well-accepted among consumers; it can be an attractive alternative for lacto-ovo vegetarians. Milk proteins are less expensive and serve as a quality source of casein and whey proteins. Soy protein may be the best choice for vegetarians and individuals interested in increasing dietary availability of isoflavones. In addition, soy is generally well-tolerated by individuals with wheat-gluten, egg, or other food allergies. Furthermore, soy is usually the least expensive protein source.

Carbohydrates controversy
A growing controversy has risen regarding what exactly constitutes a dietary carbohydrate. Many molecules being added to foods do not contain the strict one-carbon to one-oxygen to two-hydrogen (1C:1O:2H) stoichiometry usually associated with sugars. However, most of these compounds must be discussed within the general class of carbohydrates. However, the metabolic consequences of carbohydrate ingestion (insulin release, growth hormone suppression, the inhibition of lipolysis and the speeding of gastric emptying, i.e. early hunger after eating) are all items of concern for people choosing a low-carbohydrate lifestyle, not the molecule's strict chemical formula. For the sake of simplicity in this discussion, we have also taken the liberty of discussing sugars within the very broad definition of edible alcohols.

The need to keep a broad perspective when dealing with carbohydrate-type molecules is best exemplified in the case of ethanol. Although ethanol is not strictly a carbohydrate, its metabolic effects actually should classify it as a "super carbohydrate." Its calorie content is almost double most sugars (7 kcal/gram), its insulin-raising activity in the average population is dramatic, its growth-hormone suppression is profound, and its metabolic impact on visceral fat tissues (i.e. the "beer belly") is also very powerful. For this reason, the current labeling of some beers as "low carb" is misleading to those wishing to maintain a fat-burning hormonal milieu. The true metabolic impact of these beverages is actually far greater than an isocaloric load of sugar.

Another area of controversy exists around the concept of the glycemic index (GI). The GI is defined as "the incremental area under the blood glucose response curve of a 50-gram carbohydrate portion of a test food expressed as a percent of the response to the same amount of carbohydrate from a standard food taken by the same subject." A low-GI food causes a small rise in blood sugar, while a high-GI food provides a dramatic spike. Considering glucose as having a GI of 100, GI of 70 or higher is considered high, a GI of 56 to 69 is moderate and a GI of 55 or less is low. Foods with a low GI have generally been considered to be healthier than those with higher values. The aim of establishing the GI of various foods is admirable, and in some cases it helps insulin-dependent diabetics adjust their medication requirements. However, in the real world people consume mixtures of foods, and in this context the GI becomes an unrealistic approximation of what actually occurs in vivo. Although the GI concept was originally greeted with favor, its use is losing popularity. Instead, some are looking at glycemic load (GL), which takes the glycemic index of a particular food or ingredient into account, but also considers how much of that carbohydrate is in a serving of the food.

However, in the context of maintaining or reducing body fat composition in those with normal pancreatic function, no clear data shows that a long, moderate rise of glucose and insulin is in any way superior to a short, high burst. Therefore, in the absence of more data, carbohydrates should be compared on a gram-for-gram basis when determining their metabolic impact in low-carb foods.

Sweetener selections
Aside from being carbohydrates, there is nothing intrinsically harmful or toxic about small amounts of simple sugars. The choice of a simple, safe, and cheap sugar can be entertained if a formulation requires only a very small to moderate amount of sweetness. However, consider that many common sweeteners are considered "empty calories"; they provide little or nothing in the way of nutrition except calories. Some more-nutritious natural options exist. For example, blackstrap molasses contains vitamins and minerals (e.g. calcium, potassium), so it is a more nutritionally sound sugar-sweetener if it can be used. Honey is another natural sweetener that provides vitamins and minerals, such as vitamin B6, thiamin, niacin, riboflavin and pantothenic acid, calcium, copper, iron, magnesium, manganese, phosphorus, potassium, sodium and zinc, as well as several antioxidant compounds. However, food products that rely on a high level of sweetness cannot contain high levels of sugar-sweeteners and be low in carbohydrate, therefore alternative sweeteners should be considered.

Alcohols, polyols and artificial sweeteners. This broad class of chemicals may be the most controversial in the low-carbohydrate food sector. Because most of these molecules are not protein, fat, vitamin or mineral, they should be considered as a sub-class of carbohydrates.

Many polyols that avoid intestinal absorption or liver metabolism still contribute a significant caloric load to the food or beverge. Many of these calories are absorbed through the large intestine in the form of bacterial fermentation products (e.g. short-chain fatty acids and other glycolytic intermediates). The metabolic impact of these substances is still poorly understood. The effects of polyols on bowel function, however, are very well known and their untoward symptoms are hard to ignore. Diarrhea and flatulence are seen with some of these ingredients at doses as low as 10 to 15 grams.

· Erythritol is a four-carbon polyol that is rapidly absorbed by the gut, hence causes few intestinal problems. More than 90% is excreted via the urinary system. A theoretical risk of crystallization in the kidneys exists in individuals who consume large amounts if dehydrated. It has much lower caloric availability than the other common polyols.

· Glycerol, a three-carbon polyol, is completely absorbed and metabolized. Although it technically generates a small insulin response after ingestion, up to 56% of ingested glycerol is converted directly into glucose over the course of several hours in obese individuals. In all fairness and honesty, this molecule must be considered a full metabolic equivalent to carbohydrates on a gram-for-gram basis.

· Isomalt is a condensation of glucomannitol and glucosorbitol. Like many other polyols, it provides calories from peptidase hydrolysis and fermentation in the colon.

· Lactitol is a condensation of galactose and sorbitol. There is very little gut absorption of this compound, hence malabsoption symptoms can occur at low doses.

· Maltitol is a condensation of glucose and sorbitol. It owes its higher caloric content to the fact that half the molecule is a glucose moiety. Maltitol induces a postprandial insulin response at least 25% that of an equal amount of glucose.

· Mannitol is a hydrogenated mannose product that is generally known as a baby laxative. Malabsorption symptoms occur with as little as 10 grams.

· Sorbitol is created by the hydrogenation of glucose. Up to 75% of individuals experience malabsorption at doses higher than 20 grams.

· Tagatose, a chiral isomer oÊ fructose, is poorly absorbed from the gut, yet is completely metabolized by the liver once it enters the entero-hepatic circulation. This compound, therefore, provides calories both through gut fermentation and liver metabolism.

· Xylitol is a five-carbon polyol that occurs naturally in some fruits. In actual practice, its caloric content is variable since its absorption through the intestine is inducible (i.e. more is absorbed the more often it is eaten).

Super sweet
High-intensity sweeteners are often used as sugar or caloric-carbohydrate sweetener replacements, alone or with other sweeteners that provide bulk in the food product (e.g. polyols). Because of their high sweetness level, they are used in small quantities and do not replace the bulk contributed by carbohydrates.

· Sucralose, a tri-chloro-substituted sucrose molecule, has an energy content of virtually zero calories and is 600-fold sweeter than sugar. It is heat stable. Less than 30% of ingested sucralose is absorbed through the gut. Less than 5% of the compound in the systemic circulation is metabolized for excretion by glucuronidation. Conflicting numbers from various sources report between 0% and 30% is "metabolized" via various other routes. Although the sweetener is approved for use in the United Status, some have raised concerns over the possible toxicity of trace amounts of the 1,6-dichlorofructose metabolite. Definitive data is lacking to promote or refute this assertion. Because it is based on a sucrose molecule, it can be considered a polyol, and it may be the only polyol that truly deserves complete exemption from classification as a dietary carbohydrate.

Other GRAS-approved sweeteners include:
· Acesulfame K, a single heterocyclic ring, is 200 times as sweet as sucrose. It is heat stable, so it can be used in products that are cooked or heat-processed. No safety concerns have been raised about acesulfame K. The body does not metabolize this sweetener; it is excreted, unchanged in the urine.

· Aspartame, which is 180 to 200 times sweeter than sugar, consists of two proteins, aspartic acid and phenylalanine, which are esterified with a small amount of methanol. It loses sweetness when exposed to heat. The body digests it as a protein, so it provides 4 kcal per gram -- this is negligible with the normal use levels. Excessive intake of phenylalanine can pose a hazard to those with phenylketonuria (PKU). A number of negative allegations about aspartame's safety have circulated, especially the formaldehyde and formic acid that result from the breakdown of methyl alcohol when aspartame is subjected to high temperature storage, but no scientific studies support the negative health effects. Anecdotal reports suggest some people may have sensitivity to aspartame ingestion. However, regulatory and scientific advisory bodies including the FDA, Health Canada, Scientific Committee for Food of the European Community, and the Joint Expert Committee on Food Additives (JECFA) of the United Nations Food and Agriculture Organization and World Health Organization have reviewed the available safety studies and have found aspartame to be safe.

· Saccharin is about 300 to 400 times as sweet as sucrose. It consists of two rings: one phenyl ring and a heterocyclic, five-membered ring with a carboxyl group, a nitrogen in the ring, and a sulfone group next to the nitrogen. In the 1970's, its safety was questioned because of studies suggesting an increased risk of bladder cancer in male rats given very high levels of saccharin. Later, the research design was called into question and, in 1998, the International Agency for Research on Cancer (IARC) downgraded the rating of saccharin and its salts from "possibly carcinogenic to humans" to "not classifiable as to its carcinogenicity to humans."

A low-carb future
The statistics regarding obesity, type-2 diabetes, and cardiovascular disease in America are well-known and need not be repeated here. It is clear that an effective intervention to reduce this human suffering and early death has the same potential as other famous milestones in public health measures. The adoption of low-carbohydrate consumption patterns could have far-reaching beneficial ramifications and this opportunity cannot be ignored.

Currently many voices are speaking to the subject of low-carbohydrate food consumption. To the average consumer, there appears to be a lot of conflicting information and competing health claims. This confusion is hampering the prompt adoption of these products and dietary recommendations. The basic scientific tenets of this approach to regulating human metabolism are well established. Although there are still a great many questions to be answered, this industry sector has every reason to take a united stand on the current bedrock of scientific knowledge to promote its position.

 

Gil Wilshire, M.D., FACOG: is the president and chief scientific officer of the Carbohydrate Awareness Council. He is a reproductive endocrinologist with expertise in diabetes and metabolism. He has first-authored scientific research in such journals as Clinical Endocrinology and Metabolism and Fertility and Sterility. He earned his bachelor's degree in chemistry from the University of Michigan and his M.D. from the Robert Wood Johnson Medical School. He did his sub-specialty Fellowship in Reproductive Endocrinology at UMDNJ-New Jersey Medical School. He also serves as the medical director of Technology Catalysts International Corporation.