The number of different foods available to American consumers has exploded by over 4000 percent over the last 65 years, and many experts link this increase in variety with an upsurge in average body weight. although some research suggests that variety is not responsible for weight gain, a new investigation reveals that increases in variety of certain foods and decreases in variety of other edibles are associated with weight loss over the long term.

In 1938, average American grocery store stocked 800 items.

By 1983, that number had grown to 10,000 products, and today the figure is close to 35,000 (1). This is of course a wonderful development for consumers who enjoy having access to a potpourri of products, but there is one potential problem: Some experts contend that the tremendous variety of foods available today is making us fat.

At first glance, of course, the nation seems somewhat absurd. Why would the mere presence of a salmagundi of sustenance pack blubber under our skins? In fact, eating a variety of comestibles should make dining more interesting and satisfying and thus decreased the need to fill our bellies to the top in order to feel satisfied.

However, the notion that diversity in food items leads to corpulence is based on sound scientific reasoning and research. The physiological mechanism involved is something called sensory-specific satiety (SSS).

Here's how SSS works: As you eat a bowl of lentils (or rather, the lentils inside the bowl), your nervous system gradually gets used to the sensory qualities of the starchy little pellets. The first bite tastes great (provided you have seasoned the dish properly), the second mouthful not as great but still good, the third chomp less-flavorful still, and so on. Before too long, your sensory system totally loses interest in the lentils, and you tend to stop eating when your tummy feels moderately full or your hunger oangs are alleviated. If the lentils are the only item on your menu, you do not overeat. You become satiated in part because of the sensory-specific qualities of lentils, which are simply not "interesting" enough to keep your jaws moving for long. This is SSS in action.

Put a plate of General-Tso's chicken on the table along with the lentils, however, and everything changes. Tso's chicken creates novel sensations in your nose and mouth which arouse your brain and stimulate eating, and your total intake of food is greater, compared with a one-item meal. Add a platter of Chinese spare ribs to the equation (or Southern ribs, for that matter: the geographic designation has no bearing on SSS), and ingested calories continue to climb.

This effect of the hedonic qualities of foods can make a difference during one meal and over longer periods of time, as well. If you are eating beans and rice for nearly every meal, for example, your meal size will gradually get smaller over the course of several weeks (and may become vanishingly small as your taste for rice and beans turns completely sour). In contrast, if you are constantly sampling a rich array of foods, meal size will tend to be much-more robust. The presence of a variety of foods can lead to overeating; some research suggests that variety can hike daily caloric consumption by as much as 25 percent (1).

Food marketers are well aware of the pernicious effect that SSS can have on sales of their products. That's why Coca-Cola has more than 400 different kinds of drinks (1). If you are tired of Coke there is a problem - there are 399 calorie-rich Coca-Cola made quaffables to lure you away from plain water. Thanks to SSS, Frito-Lays puts close to 150 different chips and pretzels on grocery shelves around the world, and Campbell's offers 10 soups (ibid), just in case you get a bit tired of chicken-noodle pottage. In many grocery stores, breakfast cereals have their own specil aisle, a special tribute to the physiology of SSS.

True, not everyone believes that greater dietary variety can increase the risk of being overweight. Professor  Richard Mattes of Purdue University agrees that variety prompts people to eat more, but he suggests that people compensate for the extra eating at subsequent meals, eating less than they usually would and "balancing out" their daily and/or weekly caloric intakes (1). However, research carried out with laboratory animals paint a rather grim picture of dietary variety and energy intake; these studies reveal that when animals are offered a greater collection of foods, especially when the comestibles are energy-dense, the little beasties take in more energy, gain additional weight, and become fatter, compared with the provisioning of a small sample of different foodstuffs (2). Likewise, human studies suggest that individuals who have greater dietary variety tend to eat more calories per day and pack more fat into their subcutaneous and deep tissue spaces (3, 4, & 5).

So, can decreasing your food variety help you lose weight - without hurting your health (after all, variety can be a good thing, since it can broaden the spread of different nutrients which you ingest and thus decrease the risk of a vitamin or mineral deficiency)? To find out, H.A. Raynor, Rena R. WIng, and their colleagues from Brown Medical School/Miriam Hospital in Providence, Rhode Island (USA) and the School of Public Health at the University of Minnesota recently studied 121 overweight adults for a total of 18 months (6). The subjects were 25 to 50 years of age and were 14 to 32 kilograms overweight; the average BMI was 32.3 kg/m2/

The participants in the study attended weekly group meetings for six months, biweekly meetings from the seventh to 12th month of the investigation, and monthly get-togethers from month 13 through 18; during these assemblies, the subjects received instruction on the topic of diet, physical activity, appetite control, problem-solving, goal setting, social support, motivation, and relapse prevention. The individuals were divided into two groups, with the members of one group burning about 1000 caloies per week during exercise (consisting of approximately 30 minutes of medium-intensity walking per day) and individuals in the other group expending about 2500 weekly calories via exertion (with close to 75 minutes of walking each day). The basic dietary goals  were the same in the two groups: all subjects reduced daily caloric intakes to 1000 to 1500 calories and derived 20 percent of total energy from fat.

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The W.H.O. and another United-Nations group -m the Food and Agriculture Organization - think we should eat less sugar. In their new report ("The Expert Consultation on Diet, Nutrition and the prevention of Chronic Diseases"), the two bodies suggest strategies for dietary changes in individuals, one of which is to cut back significantly on sugar consumption. Why is sugar under attack by these international organizations? Obesity is now a global epidemic, with more than one billion people in the world classified as overweight or obese. Heart disease and type-II diabetes (the top-two health consequences of obesity) are surging past malnutrition as the most significant world-wide health problems (1). International groups such as W.H.O. and the F.A.O. think that something has to be done quickly. Sugar - with its relatively high calorie content, total lack of nutrients, and near omnipresence in energy dense snack foods - is a convenient target.

The W.H.O. and F.A.O. report is particularly tough on "free sugar." Such emancipated muscovado is the sugar which is added to foods - the sucrose, high fructose corn syrup, honey, and, molasses in soft drinks, snack foods, pastries, and candies, for example. It also refers to sugar piled into foods which are not usually thought of as being sweet - such as mayonnaise and peanut butter (1). According to the report, no more than 10 percent of your daily calories should come from free (added) sugars.

Unfortunately, added sugars already accounted for about 11 percent of the calories in Americans' diets in 1979, and their contribution has soared to 16 percent today. For teen-agers swigging sodas and extracting snacks from coin machines in their middle and high schools, the sugar "gift" to the daily caloric budget is a whopping 20 percent. A regular can of Coke or Pepsi possesses about 140 to 150 calories and around 10 teaspoons of sugar, while a single, 20-ounce Coke or Pepsi pushes a full 15 teaspoons of sugar into an imbiber's gullet. The average American citizen now drinks 52.3 gallons of soda per year, an incredible quota of one gallon per week (2)! In contrast, the "man on the street" quaffs just 20 gallons of milk per year and 16.6 gallons of water (ibid). As Americans have increased their added-sugar consumption, they have steadily gotten fatter, too.

Naturally, individuals who make their living by selling sugar are not happy with the report. The "Sugar Association" deplored the "dubious nature" of the treatise and even asked Congress to revoke the United States' $406-million annual contribution to the W.H.O. Senators Larry Craig and John Breaux, who happen to be co-chairmen of the "Senate Sweetener Caucus" (yes, there really is such a committee), actually asked Health-and Human-Services Secretary Tommy Thompson to implore the W.H.O. to "cease further promotion" of the report. Trade association for the corn-refining and snack food industries questioned the report's legitimacy (1).

Unhappily for these sugar-promoting organizations, sugar took an even harder hit very recently when nutritionists and epidemiologist from Harvard School of Public Health published  study linking the consumption of sugar-sweetened soft drinks with both weight gain and an increased risk of developing type-2 diabetes (2). This research tracked 52,000 nurses' dietary habits and health records.

In the study, "sugar" included high-fructose corn syrup, the kind of sweetener often used in soft drinks and other beverages. The Harvard white coats compared nurses who swilled less than one sugar-sweetened beverage a month with those who guzzled as many as one or more daily and found that a greater consumption of sugar sweetened drinks was connected with both diabetes and weight gain.

The Harvard investigation is a "cohort study," which simply means a large group of people who have something in common have been followed for a significant period of time. These kinds of studies have yielded some of the best current information regarding the link between diet and health (3). For example, the Physicians' Health Study, another cohort inquiry, followed over 20,000 male physicians for over a decade and found that doctors who took a daily dose of aspirin had a 44-percent lower risk of heart attack, compared with aspirin-free docs; this same cohort study was able to show that supplementation with the anti-oxidant beta-carotene was neither beneficial nor harmful with respect to the risks of heart disease and cancer.

Somewhat surprisingly, the increase in diabetes risk among nurses in the Harvard study was present across disparate categories of people. For example, the likelihood was heightened in both obese and non-obese women, in those with high rates of physical activity and low rates of exertion, and in those consuming lots of "trans" fats and those eating little of this unhealthy type of fat. Women consuming the most sugared soft drinks had an 83-percent great risk of developing diabetes, compared with females drinking the least. Fruit punch also got in on the action, doubling the risk of diabetes in women who were most "punchy." However, there was no link between the consumption of 100-percent fruit juice and diabetes or obesity.

True, the biggest drinkers of sweetened soft drinks in the Harvard study tended to be less physically active, to smoke more, to consume greater numbers of calories, and to eat less protein, magnesium, and cereal fiber. To some, this might suggest that unhealthy lifestyle, rather than the consumption of sugared drinks, was the key culprit underlying the trend toward fatness and diabetes. However, the Harvard researchers juggled the data so that the effects of these other factors were essentially removed, and when they did so the link between sugared drinks and poor health remained. As you might expect, diet sodas got a free pass; consumption of these sugars-free quaffables was not linked with diabetes or obesity. As mentioned, pure fruit juice (with no added sugar) was also in the clear.

Summarizing the findings, Boston-University physician Caroline Apovian wrote that the research provided "strong, scientifically sound evidence that excess calories from soft drinks are directly contributing to the epidemics of obesity and type-2 diabetes, at least in the U.S." (2) The Harvard study lends support to a previous, long-term (19-month), observational study which detected a positive relationship between the intake of sugar sweetened drinks and the risk of childhood obesity (4).

Note, though, that the Harvard cohort study actually calls into question the consumption of sugared drinks, not the intake of sugar per se. It might be that there is something about the presence of sugar in soft drinks which makes it particularly pernicious - and that sugar placed in solid food, for example, might have no specific effects on weight gain and the risk of diabetes. The reason for this might be that the sugar in soft drinks is absorbed more easily and quickly, compared with the sugar which is "riding along" with protein and fat in solid food. Quick absorption of soda sugar, repeated over and over again over the course of weeks and years, could keep one's poor pancreas on a roller-coaster ride and could eventually make one's tissues resistant to the flood tides of insulin washing through the blood on a regular basis. The rapid rises and consequent steep falls in blood sugar associated with sugared-drink intake could also reduce satiety and spur appetite, leading to an increased chance of being overweight. Note, too, that research suggests that compensation of energy intake (a situation in which a sizable intake of calories leads to reduced consumption later) is less accurate when energy is taken via liquids, compared with in solid foods (5). If sugary liquids are truly associated with faulty compensation, they would be more likely to promote a positive energy balance, compared with sugary solid food.

So, what does other research say about the role that sugar plays determining body weight? Are sugared soft drinks the villain, or is sugar in general a "bad guy"?

A classic way to explore the notion that sugared soft drinks are "evil" has been to replace the sugar in soft-drink-consumers' diets with artificial sweeteners; if the sugar in the drinks really makes people fat, soft-drink-swillers should in theory lose weight when the sugar is taken away and a calorie-free sweetener is put in. There are troubles with this thinking, though. Although the concept sounds nice, it is possible that weight would be lost not because sugar was removed but because total caloric intakes dropped - and that the elimination of calorically equivalent amounts of protein, fat, or complex carbohydrate would have had the same body-trimming effect.

That's true, of course, but the problem is that people do drink soda. Since they are going to be drinking soda, we might as well let some of them drink sugar-rich soda, while others take in only the artificially sweetened stuff. We can then see if the sugary sodas are a problem. It is not entirely obvious that they would lead to weight gain, since the sugar intake could lead to less outside-the-soda-bottle caloric ingestion, compared with the artificially sweetened case (with the added calories from sugared sodas, people might need to eat less at other times). Alternatively, the artificially sweetened folks could actually compensate for their reduced caloric intakes by stepping up their total food consumption.

Interestingly enough, the evidence suggests that replacing sugared sodas with the artificially sweetened kind does lead to better weight (2.6 kilograms, or 5.7 pounds) during the year following a 19-week weight-loss program, compared with females who ingested sugar-containing foods and drinks (the latter individuals packed on more than double the weight - 5.4 kilos, or nearly 12 pounds). After two years of follow-up, the aspartame utilizers still enjoyed a total weight loss of 5.1 kilograms (11.2 pounds), while the sugar-eaters had gained back all of the weight dropped during the initial 19-week program (6). The simple lesson from the study is that replacing sugar with an artificial sweetener such as aspartame can lower the risk of regaining lost weight. A separate investigation carried out in Spain with 2450 men and women found that the intake of cyclamate, another artificial sweetener, was negatively correlated with body-mass index (BMI); the greater the consumption of cyclamate, the lower the risk of being overweight (7).

To learn more about Is Sugar Not-So-Sweet For Weight Loss (the full article can be read by purchasing Vol.1 Issue 5) and many more weight-loss related topics. Simply click on Back Issues, then select Vol. 1 Issue 5 from the drop-down menu. Or enter any subject you wish to learn more about.