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European Journal of Clinical Nutrition (1999) 53, 757±763 ß 1999 Stockton Press. All rights reserved 0954±3007/99 $15.00 http://www.stockton-press.co.uk/ejcn Review Intense sweeteners and energy density of foods: implications for weight control A Drewnowski1* 1 Departments of Epidemiology and Medicine, and Nutritional Sciences Program, University of Washington, Seattle, WA, USA Energy density of foods, as opposed to their sugar or fat content, is said to be a key determinant of energy intakes. Recent laboratory studies have shown that, under ad lib conditions, subjects consume a constant weight or volume of food, so that their energy intakes depend on the energy density of the diet. Because low energydensity foods provide fewer calories per eating bout, they should Ð in theory Ð lead to reduced energy intakes and therefore weight loss. However, there is some question whether energy-dilute foods are as palatable as the more energy-dense foods. Generally high energy density equals high palatability and vice versa. Intense sweeteners represent an exception to the rule, since they maintain sweetness while reducing energy density. While many studies have explored the effects of intense sweeteners on short-term regulation of food intake, fewer studies have addressed the effectiveness of intense sweeteners in reducing energy density for weight control. Issues of energy density, palatability, and satiety, as applied to intense sweeteners are the topic of this review. Descriptors: Energy density; palatibility; satiation; intense sweeteners Introduction Human obesity is the outcome of excess energy intake and insuf®cient energy expenditure (West & York, 1998). Studies of dietary factors in obesity have mostly focused on intakes of sugar and fat and on the nutrient composition of the diet (Lissner & Heitmann, 1995; Bray & Popkin, 1998). At one time or another, obesity was associated with excessive consumption of fat (Lissner & Heitmann, 1995), sugar (Harnack et al, 1999), starches (Stubbs et al, 1997), or even protein (Parizkova & Rolland-Cachera, 1997). However, the percentage of energy from a given nutrient, as opposed to total calories, may not be the primary cause of obesity. The contribution of dietary fat to obesity has been sharply questioned (Willett, 1998) and it is unclear that any single nutrient is to blame. Research attention is turning toward a new dietary variable: energy density, de®ned as the amount of available energy per unit weight (Poppitt & Prentice, 1996). An increasing number of studies now address energy density of foods and the mean energy density of the diet (Poppitt & Prentice, 1996; Prentice & Poppitt, 1996; Rolls et al, 1999; Drewnowski, 1998). Energy density, as opposed to the macronutrient content of foods, is increasingly viewed as the key factor in the regulation of food intake (Poppitt & Prentice, 1996; Prentice & Poppitt, 1996; Rolls et al, 1999; Drewnowski, 1998). Under ad libitum conditions, laboratory subjects appear to consume a roughtly constant weight of food, as opposed to a constant amount of energy (Poppitt & Prentice, 1996; Prentice & Poppitt, 1996). In theory then, selecting foods with low energy-density ought to lead to *Correspondence: Dr Adam Drewnowski, 305 Raitt Hall Box 353410, University of Washington, Seattle, WA 98195-3410, USA. Received 19 November 1998; revised 12 March 1999; accepted 23 June 1999. lower energy intakes and therefore weight loss. However, not all researchers agree that the volume of food consumed is, in fact constant, or that the regulation of food intake in real life involves modulating energy density, as opposed to the weight or volume of foods. Nonetheless, lowering energy density of foods is viewed as a viable option for obesity treatment (Rolls et al, 1999). Obese women, thought to consume excessive amounts of sweet high-fat foods, might be the chief bene®ciaries of this approach. The volume of food can be expanded by the addition of water, ®ber, or even air (Drewnowski, 1998). However, unless palatability is kept constant, the resulting food product may not be acceptable to the consumer (Drewnowski, 1998). Intense sweeteners successfully lower energy density of foods and beverages without sacri®cing sweetness or good taste. Their in¯uence on short-term regulation of food intake has been explored previously (Rolls, 1991; Renwick, 1994; Drewnowski, 1995 for reviews). Their ef®cacy in aiding weight control, as predicted by the energy density hypothesis, is addressed in this review. What is energy density? Energy density is largely determined by the water and fat content of foods. An analysis of approximately 100 foods from a food frequency questionnaire (Drewnowski, 1998), showed that the more energy-dense foods contained less water per 100 g (see Figure 1). As shown in Figure 2, energy-dense foods also contained more fat per unit weight (Bray & Popkin, 1998). Together, water and fat content accounted for 99% of the variance. As might be expected, energy-dilute foods included beverages, soups, salads, vegetables, and fruit. In contrast, energy-dense foods Intense sweeteners and weight control A Drewnowski 758 Figure 1 A scatterplot of water content (g=100 g) and energy density (kcal=g) of approximately 100 foods from a food frequency questionnaire. Figure 2 A scatterplot of fat content (g=100 g) and energy density (kcal=g) of approximately 100 foods from a food frequency questionnaire. included dry cereals, packaged snacks, sweets and desserts. Typically, energy-dense foods were dry and contained fat, added sugar, or both, whereas energy-dilute foods contained water, dietary ®ber, starch, or sometimes protein (Drewnowski, 1998). Obesity and energy density Increasing rates of obesity worldwide have been linked to overeating of sweet and high-fat foods (Drewnowski & Popkin, 1997). Diets of developed nations are more energydense and tend to provide more calories per unit volume than the traditional plant-based diets, with a higher proportion of complex carbohydrates and ®ber. This nutrition transition has been accompanied by increasing urbanization, mechanized transport and lower levels of physical activity. It is therefore unclear whether high rates of obesity in af¯uent societies are a direct consequence of energy density of the diet, as opposed to the basic imbalance between energy intake and energy expenditure. In any case, there are no data to link obesity with energy density of the diet. Sensory studies suggest that obese women prefer sweet and fat-rich foods (Drewnowski, 1986). Studies of food preferences showed that obese women gave high ratings to sugar=fat mixtures such as doughnuts, cakes, cookies, chocolate candy and other desserts. In contrast, obese men tended to favor meat dishes and other combinations of fat and salt (Drewnowski, 1997). Arguably, the diet of obese persons might be higher in energy-dense foods that are high in fat, sugar and salt. However, no study has compared mean energy density of the diet of obese as opposed to lean individuals. Using foods with low energy density is a common strategy for weight control. By current estimates, 39% of American women and 25% of men and trying to lose weight, mostly by reducing their intakes of sugars and fats (Levy & Heaton, 1993). Intense sweeteners play an important role. Among the most frequent weight loss practices were the use of diet soft drinks (by 52% of women and 45% of the men) and of tabletop intense sweeteners (43% of women and 33% of men). While these practices precede current interest in energy density of foods, the use of intense sweeteners to reduce energy density ought to promote satiation, reduce energy intakes, and thereby aid weight control. This regulatory mechanism is based on a postulated relationship between energy density and satiating power of foods. Reported overeating of palatable sweet and highfat foods has been ascribed to their high energy density and to their weak satiating power (Green et al, 1994). Assuming that people consume a constant mass of food per day, eating foods with lower energy-density, that is fewer calories per unit weight, should reduce energy intakes overall. And since energy-dilute foods are more bulky, they ought to have higher satiating power (Holt et al, 1991). A high-volume energy-dilute diet should thus promote satiety and encourage weight loss. In principle then, diet soft drinks with an energy density of zero ought to promote satiety very effectively indeed. Regulation of food intake Energy density and palatability The sweet taste of sugar is both pleasurable and rewarding (Drewnowski, 1986). All children love sweets, correctly associating sweetness with nutritive energy from sugar (Drewnowski, 1986; 1997). Studies show that novel tastes and ¯avors can become preferred provided they are associated with another high-density energy source, such as fat (Johnson et al, 1991; Birch, 1992). This innate pleasure response to sweet and high-fat foods may have a metabolic basis (Drewnowski et al, 1995). Whereas selective fat appetite is said to depend on galanin and neuropeptide Y (Leibowitz & Kim, 1992), preferences for sweets may involve the endogenous opiate peptide system (Drewnowski et al, 1995). Exposure to sweet taste is thought to lead to the relese of endogenous opiates, explaining perhaps why sweet snacks are sometimes consumed in times of stress. Given the neural mechanisms of food reward, it is not surprising that food palatability and energy density should be linked. Foods that deliver concentrated energy per unit volume are generally preferred over those that do not. Though some investigators believe that energy density and palatability are independent variables, diluting energy density of foods through the addition of water, ®ber, or Intense sweeteners and weight control A Drewnowski protein usually leads to a reduction in palatability. The range across which energy density can be reduced without affecting palatability is quite limited. While a 2% yogurt and a fat-free yogurt can be matched for palatability, boiled spinach (0.1 kcal=g) will never be as palatable as chocolate (6 kcal=g). Those studies that manipulated energy density while keeping palatability constant used foods whose energy density was already low (Drewnowski, 1998). Generally, the difference between `high' and `low' energy density foods was between 1.6 and 1.1 kcal=g (Rolls et al, 1999; Drewnowski, 1998). Intense sweeteners are mostly used in diet beverages and `light' semi-solid foods, such as yogurts, puddings and frozen desserts. The reduction in energy density is in the order of 0.4 kcal=g. As shown in Table 1 the use of intense sweeteners in diet soft drinks and beverage mixes reduced energy density from 0.40 kcal=g to zero, while the energy density of yogurts, puddings and frozen dessers, generally in the 0.8 ± 1.0 kcal=g range, was reduced by half. For comparison purposes, the nonabsorbable fat replacement product Olestra reduces energy density of potato chips from approximately 4.5 to 2.5 kcal=g. Palatability and satiety Palatability and satiety have opposite effects on food consumption. While food palatability increases appetite and thereby energy intakes, satiety limits intakes by reducing meal size or by delaying the time of the next meal (Blundell et al, 1996; Rolls et al, 1994; Rolls, 1995). Among chief measures of palatability are perceived pleasantness of a given food, intent to eat, or the amount of food consumed (Birch, 1992). Satiety, de®ned as internal state of energy repletion after a meal, has been measured in terms of fullness, reduced hunger, or reduced intent to consume a meal or a snack (DeGraaf et al, 1993; Green & Blundell, 1996; Rolls et al, 1990). Satiety has also been measured in terms of reduced palatability. Sensory speci®c satiety was speci®cally de®ned as reduced palatability of the just-consumed food relative to other foods (Rolls, 1986). With satiety measured in terms of palatability and vice versa, the relationship between the two is, by de®nition, reciprocal (see Table 2). Whereas palatable foods Ð such as sugar and fat Ð are reported to be less satiating, the more satiating foods are, as a rule, less palatable (Holt et al, 1991). As might be expected, the best tasting, but least satiating, foods are those that are energy-dense, sweet, or rich in fat (Drewnowski, 1986; 1987; 1995; Drewnowski & Greenwood, 1983). Energy density, palatability and satiety The satiating power of different foods may depend on their energy density or nutrient composition (Poppitt & Prentice, 1996; Prentice & Poppitt, 1996; Burley et al, 1993; Rolls et al, 1988). Protein and carbohydrate are thought to be more satiating than fat. In one study (Holt et al, 1991), subjects rated satiety every 15 min for 2 h after consuming equicaloric (240 kcal) portions of 38 common foods. Satiety index (SI) was calculated by dividing the area under the satiety response curve for each food by mean satiety curve for white bread and multiplying by 100. Satiety was most highly correlated with the volume of food consumed, which ranged from a low of 38 g for peanuts to a high of 625 g for oranges. Chocolate was the least satiating food, while vegetables and fruit were more satiating. Boiled potatoes, porridge and ®sh were more satiating than cookies or cakes. Satiating power was linked to low energy-density and high levels of protein, ®ber, and water (Holt et al, 1991). As might be expected, SI and hedonic preferences were inversely linked. Table 2 A comparison of palatable vs satiating foods Nutrient composition Volume per portion Energy density (kcal=g) Sensory features Palatability Example foods Palatable foods Satiating foods High sugar High fat Low High Sweet, fat High Chocolate Potato chips Cakes, pastries High protein High ®ber High Low Watery Low Porridge Spinach, potatoes Fish Table 1 Principal measures of hunger, appetite, and satiety in laboratory tests Motivational states Taste response Desire to eat Speci®c appetites Food consumption Principal measures Reference Hunger Satiety Fullness Oversatiety (overfullness) Nausea Reduced pleasantness of sweet stimuli Reduced pleasantness of food odors Reduced appeal of just-consumed foods Desire or intent to consume Appetite for a meal Appetite for a snack Appetite for something sweet Appetite for something savory Pleasantness of something sweet Pleasantness of something savory Amount of food consumed Size of test meal Delay till the next meal Dietary intake assessment (24 h) DeGraaf et al, 1993; Green & Blundell, 1996. Holt et al, 1995; DeGraaf et al, 1993; Green & Blundell, 1996. DeGraaf et al, 1993. DeGraaf et al, 1993. Rolls, 1986. Rolls, 1986. DeGraaf et al, 1993. DeGraaf et al, 1993. DeGraaf et al, 1993. DeGraaf et al, 1993. Blundell et al, 1996. Blundell et al, 1996. 759 Intense sweeteners and weight control A Drewnowski 760 Figure 3 A scatterplot of mean hedonic ratings and energy density of foods. Data from Meiselman et al (1974). Energy-dense foods containing sugar and fat were least satiating, though most palatable. Studies of US military personnel, conducted by Meiselman et al, (1974) also showed a relationship between hedonic preferences and energy density of foods. Subjects, predominantly young males, preferred meat dishes and desserts over diet beverages, vegetables and fruit. Data for 115 out of more than 300 food questionnaire items used by Meiselman et al (1974) are shown in Figure 3. Diet beverages and satiety Studies on diet beverages and satiety are extremely skewed in favor of very short-term studies. Typical study design tested hunger, satiety, and energy intakes during a single meal or snack following ingestion of a sweet stimulus. The time interval between the beverage and the next meal was very short, most often between 30 and 60 min. Most studies used beverages (Anderson et al, 1989; Birch et al, 1989; Black et al, 1991; Rolls et al, 1990), occasionally pudding or cereal (Mattes, 1990; Rolls et al, 1988; Rolls et al, 1989), with the difference between the high- and the lowenergy versions rarely exceeding 200 kcal (Burley et al, 1993; Drewnowski 1986). Some studies (Drewnowski et al, 1994a; 1994b) used a stronger energy manipulation (400 kcal), a longer time interval (2 ± 3 h), and three consecutive test meals: lunch, snack, and dinner consumed for up to 10 h post ingestion. Since the volume of the test beverage was kept constant while energy content varied, energy density was the key manipulated variable. Short-term perception of hunger and satiety ws in¯uenced more strongly by preload volume than by any other variable. A 560 mL portion of energy-free carbonated mineral water reduced desire to eat more effectively than a 260 mL portion (Black et al, 1993). In turn, 560 mL of mineral water and an equal volume of aspartame-sweetened soft drink had comparable effects on satiety. Replacing sucrose with aspartame lowered energy density of soft drinks from 0.4 kcal=ml to zero, but had no effect on immediate hunger ratings. Children, aged 9 ± 10 y, had similar hunger ratings after consuming sucrose (90 kcal) or aspartame-sweetened (3 kcal) soft drinks (Birch et al, 1989). Adults who consumed sucrose- or aspartame- Figure 4 Rated intent to eat following the consumption of breakfasts sweetened with sucrose or aspartame. Subjects were 12 normal-weight females. Breakfasts A and B had energy density of 1.4 kcal=g; breakfasts C and D had energy density of 0.6 kcal=g. From Drewnowski et al (1994a). sweetened lemonade (166 kcal vs 5 kcal showed similar hunger ratings as measured 0, 30, and 60 min later (Rolls et al, 1990). Adults who consumed a high- or low-calorie pudding or a gelatin dessert (mean energy difference: 206 kcal) also had similar ratings of hunger and desire to eat 120 min later (Rolls et al, 1989). The volume of food consumed, rather than small differences in sweetness or energy value, determined hunger and satiety in the short term. Similar results were obtained with solid and semi solid foods (Rogers & Blundell, 1989). Two studies (Levy & Heaton, 1993; Green et al, 1994) used breakfasts of yogurtlike creamy white cheese (fromage blanc) that were either plain, sweetened with aspartame or sucrose, or sweetened with aspartame and supplemented with maltodextrin. A difference in energy density of 0.6 kcal=g vs 1.4 kcal=g (weight 500 g) had no initial impact on ratings of hunger or the intent to eat in 12 normal-weight women (Drewnowski, 1993). However, as shown in Figure 4, the low-energy condition led to increased motivational ratings 2.5 h later. While the low energy-density version was as satisfying initially as the high energy density version, it was associated with increased hunger ratings later on. However, the elevated hunger ratings did not lead to compensatory eating at lunch. Energy compensation Some investigators (Rogers & Blundell, 1989; Rogers, 1993) have argued that diet products lead to false energy savings, since compensatory eating occurs during the next meal or later during the day. The ingestion of saccharinsweetened (131 kcal) as opposed to glucose-sweetened yogurt (295 kcal) reportedly led to complete energy compensation in a meal 60 min later (Black et al, 1993). Birch et al (1989) showed that 2 ± 5 y old children compensated perfectly for calories removed from soft drinks by the use of intense sweeteners. Complete energy compensation was also observed in a longer-term residential study, conducted with six normal-weight, non-dieting males (Foltin et al, 1990). The carbohydrate content of lunch was reduced by 400 kcal, mostly by substituting aspartame for sugar. Subjects made up for the energy de®cit by dinner time on every day of the experiment (Foltin et al, 1990). Intense sweeteners and weight control A Drewnowski Table 3 761 Intense sweeteners and energy density of foods Portion size (g) Energy (kcal) Energy density (kcal=g) Sugar (g=100 g) Water (g=100g) Regular soda Diet soda Lemonade, dry mix Diet lemonade, dry mix Jell-O Jell-O (sugar-free) Banana cream pudding Banana cream (sugar-free) Yogurt, fat-free Yogurt, fat-free `light' 370 370 240 240 140 121 147 130 170 170 155 1 102 5 81 8 165 88 160 90 0.42 0.01 0.42 0.02 0.60 0.07 1.1 0.7 0.94 0.53 10.4 0 11.2 0 13.4 0 19.3 0 17.7 5.9 89 100 89 99.5 85 85 73 84 N/A N/A N=A not applicable. Other studies observed either partial energy compensation or none (Anderson et al, 1989). Men and women given low- or high-calorie versions of a pudding or gelatin dessert consumed similar amounts of food at a buffet lunch presented 2 h later (Rolls et al, 1989). In another study (Rolls et al, 1990), aspartame-sweetened lemonade led to energy compensation when lunch was presented 30 or 60 min later, but not when lunch and lemonade were consumed at the same time. In a study of normal-weight men and women (Drewnowski et al, 1994a), a 400 kcal de®cit at breakfast time led to slightly higher energy intakes at lunch (111 kcal). No energy compensation was observed at later meals, such that low energy-density breakfasts resulted in lower energy intakes by the end of the day. The extent of energy compensation may depend on the subjects' sex and age, their habitual diet, and dietary restraint. Rolls et al (1994) found near-perfect energy compensation among non-dieting young men, but variable results with a group of restrained women. In contrast, a recent study of 14 restrained women (Lavin et al, 1997) reported not only complete compensation but rebound eating. In that study (Lavin et al, 1997), fourteen restrained female subjects consumed four 330 ml soft drinks during the day, while being provided with lunch, evening meal, and unlimited access to high-fat and high-carbohydrate snacks. The drinks were lemonade sweetened with 80 g of sucrose (1.0 kcal=ml), lemonade sweetened with aspartame (0 kcal=ml) and carbonated mineral water. As in past studies, no differences in hunger or fullness ratings were observed, suggesting that the subjects were insensitive to 320 kcal versus none. However, energy compensation did occur and total daily energy intakes across the three experimental conditions were the same. The aspartame condition was followed by elevated energy intakes on the next day (Lavin et al, 1997). However, the data were somewhat atypical. Despite dietary restraint, the young women consumed a mean of 3000 kcal=d, including up to 168 grams of fat in the aspartame condition. On the ®rst day of testing, mean percentage of energy from fat was 46%, while on the second day alcohol intakes reached a mean of 22 g, equivalent to four drinks. Most recent studies suggest that energy from carbohydrate, when ingested in a beverage as opposed to a solid food, may fail to provoke a compensation response, at least in the short-term (Mattes 1996). In a study of soft drinks consumption, 24 subjects failed to compensate for additional energy from sucrose-sweetened mineral water (0.4 kcal=g) during lunch and dinner on experimental days or on the following day (Beridot-Therond et al, 1998). Control of body weight Only a few clinical and epidemiological studies have addressed long-term use of intense sweeteners. An early clinical study by Porikos et al (1982) showed that replacing sucrose with aspartame over a period of 11 d led to partial (40%) compensation for the missing sucrose calories. In another study (Tordoff & Alleva, 1990), the consumption of 1135 mL of aspartame-sweetened as opposed to fructosesweetened soda daily for 21 d was associated with lower energy intakes in both male and in female subjects. Male subjects also lost weight during the 3-week period. The calorie savings derived not from a reduction in food intake but from a decline in energy derived from soft drinks. Regular users of intense sweeteners may learn to compensate accurately for the missing calories (Bellisle & Perez, 1994; Louis-Sylvestre et al, 1989). If so, then intense sweeteners will have little impact on the long-term control of food intake or body weight. A recent study of extended use of reduced-sugar foods by non-obese free-living females (Gatenby et al, 1997) showed that the subjects did reduce sucrose intakes relative to control groups. However, there were no differences in total sugars or in carbohydrate consumption and no differences in body weight over the study period were observed. Casual use of diet products may have little impact on total energy intakes or body weight status (Gatenby et al, 1997). Studies of intense sweeteners in obesity treatment are even more limited. In a pilot study of obese outpatients (Kanders et al, 1988; Blackburn et al, 1993), 46 female users of aspartame lost slightly more weight (7.4 kg as compared to 5.8 kg) when they supplemented a low-energy diet with aspartame-sweetened foods and beverages; however, a small group of male subjects (n 11) showed the opposite trend. At the 1-y follow up, maintenance of lower body weight was predicted by increased physical activity levels, reduced preference for sweets, and higher consumption of aspartame-sweetened foods. A later clinical study (Blackburn et al, 1997) recruited obese women for a multidisciplinary 17-month weight control program. A total of 163 women were randomly assigned to one of two groups, being asked either to abstain from or to freely consume aspartame-sweetened foods and beverages during the weight loss phase (16 weeks), a 1-y maintenance program, and a 2-y follow-up period. The active phase was based on a 1500 kcal diet, composed of 24% fat, 56% carbohydrate, and 20% protein, and an exercise prescription for 200 min physical activity per week. Monthly group sessions and annual follow ups were part of the program. Intense sweeteners and weight control A Drewnowski 762 At the end of the active weight loss period, the aspartame group consumed a mean of 0.29 g aspartame per day, approximately equivalent in terms of sweetening power (for liquids) to 150 g of sucrose. While the reported range of aspartame intakes was from 0.075 to 0.53 g=d, it is impossible to estimate the energy density of the diet. Exercise prescription seemed to be effective; subjects who initially reported a mean of 4 min of physical activity per week increased activity levels to > 2 ± 3 h per week (Blackburn et al, 1993). While the initial weight loss (10% of initial body weight) was comparable for the two groups, the aspartame group showed better weight maintenance during the followup period. Speci®cally, participants in the aspartame group regained only 2.6% of initial body weight after 71 weeks and 4.6% after 175 weeks. In contrast, participants in the no-aspartame group experienced an average weight regain of 5.4% and 9.4%, respectively. The aspartame group lost signi®cantly more weight overall and regained signi®cantly less weight during maintenance and follow-up than did the no-aspartame group (Blackburn et al, 1993). These data suggest that while aspartame per se does not promote rapid weight loss, the inclusion of aspartame sweetened products in a multidisciplinary weight control program may promote the long term maintenance of reduced body weight (Blackburn et al, 1997). Whether the aspartame group consumed a more energy-dilute diet is, of course, the key question. Conclusions: sweeteners in a healthy diet As incomes rise and populations become more urban, traditional plant-based diets high in complex carbohydrates and ®ber give way to more varied diets that incorporate more meat and animal products. Such diets are more energy dense, since they derive a higher percentage of energy from animal protein, starches, sugars, and fats (Drewnowski & Popkin, 1997). Faced with the health consequences of over-nutrition, the food industry has sought to increase the satiating value of foods (Drewnowski, 1993). One strategy has been to reduce energy density by increasing food bulk and volume. However, substituting water, ®ber and protein for the more energy-dense (and more palatable) sugar and fat can result in bland and monotonous diets. Few dieters adhere to energy-dilute diets for very long (Drewnowski, 1998). Though naturally energy-dilute foods such as raw vegetables and fruit are widely distributed in the food supply, many consumers prefer to lower the energy density of their diet by using intense sweeteners and fat replacement products. Intense sweeteners offer a very effective method of reducing energy density of foods while maintaining their palatability (Drewnowski, 1995). According to current theories on energy density and satiety, palatable diet soft drinks provide volume and therefore affect satiety, even though their energy density is zero. However, most studies on intense sweeteners and energy density have been short-term ones, and our understanding of energy density issues is therefore limited. Whether the energy density approach to weight reduction will be effective in the long term still remains to be determined. References Anderson GH, Savaris S, Schacher S, Zlotkin S, Leiter LA (1989): Aspartame: effect on lunch-time food intake, appetite and hedonic response in children. Appetite 13, 93 ± 103. Bellisle F, Perez C (1994): Low-energy substitutes for sugars and fats in the human diet: Impact on nutritional regulation. Neurosci. Biobehav. Rev. 18, 197 ± 205. Beridot-Therond ME, Arts I, Fantino M, de la Gueronniere V (1998): Short-term effects of the ¯avor of drinks on ingestive behaviors in man. Appetite 31, 67 ± 81. Birch LL, McPhee L, Sullivan S (1989): Children's food intake following drinks sweetened with sucrose or aspartame: time course effects. Physiol. Behav. 45, 387 ± 395. Birch LL (1992): Children's preference for high-fat foods. Nutr. Rev. 50, 249 ± 255. Black RM, Tanaka PA, Leiter LA, Anderson GH (1991): Soft drinks with aspartame: effect on subjective hunger, food selection and food intake in young adult males. Physiol. Behav. 49, 803 ± 810. Black RM, Leiter LA, Anderson GH (1993): Consuming aspartame with and without taste: Differential effects on appetite and food intake of young adult males. Physiol. Behav. 53, 459 ± 466. Blackburn G, Kanders B, Lavin P, Joy P, Pontes M, Folan A (1993): Aspartame facilitates weight loss and long-term control of body weight. Int. J. Obesity 17, (Suppl 1), 46. Blackburn GL, Kanders BS, Lavin PT, Keller SD, Whatley J (1997): The effect of aspartame as part of a multidisciplinary weight-control program on short- and long-term control of body weight. Am. J. Clin. Nutr. 65, 409 ± 418. Blundell JE, Lawton CL, Cotton JR, Macdiarmid JI (1996): Control of human appetite: implications for the intake of dietary fat. Ann. Rev. Nutr. 16, 285 ± 319. Bray GA, Popkin BM (1998): Dietary fat does affect obesity! Am. J. Clin. Nutr. 68, 1157 ± 1173. Burley VJ, Paul AW, Blundell JE (1993): In¯uence of a high-®bre food (myco-protein) on appetite: effects on satiation (within meals) and satiety (following meals). Eur. J. Clin. Nutr. 47, 409 ± 418. DeGraaf C, Schreurs A, Blauw YH (1993): Short-term effects of different amounts of sweet and nonsweet carbohydrates on satiety and energy intake. Physiol. Behav. 30, 833 ± 843. Drewnowski A, Greenwood, MRC (1983): Cream and sugar: human preferences for high-fat foods. Physiol. Behav. 30, 629 ± 633. Drewnowski A Sweetness and obesity (1986) In: Sweetness and obesity, Dobbing J (ed). ILSI Nutrition Foundation Symposium, Berlin: Springer-Verlag, pp. 177 ± 192. Drewnowski A (1987): Fats and food texture: sensory and hedonic evaluations. In: Food texture, Moskowitz HR (ed). Marcel Dekker Inc., New York pp. 217 ± 250. Drewnowski A (1993): Low-calorie foods and the prevalence of obesity. In: AM Altschul (ed). Low-calorie foods handbook. Marcel Dekker Inc., New York pp. 513 ± 534. Drewnowski A, Massien C, Louis-Sylvestre J, Fricker J, Chapelot D, Apfelbaum M (1994a): Comparing the effects of aspartame and sucrose on motivational ratings, taste preferences, and energy intakes in humans. Am. J. Clin. Nutr. 59, 338 ± 345. Drewnowski A, Massien C, Louis-Sylvestre J, Fricker J, Chapelot D, Apfelbaum M (1994b): The effects of aspartame versus sucrose on motivational ratings, taste preferences, and energy intakes in obese and lean women. Int. J. Obesity 18, 570 ± 578. Drewnowski A, Krahn DD, Demitrack MA, Nairn K, Gosnell BA (1995): Naloxone, an opiate blocker, reduces the consumption of sweet high-fat foods in obese and lean female binge eaters. Am. J. Clin. Nutr. 61, 1206 ± 1212. Drewnowski A (1995): Energy intake and sensory properties of food. Am. J. Clin. Nutr. 62 (Suppl), S1081 ± S1085. Drewnowski A (1995): Intense sweeteners and the control of appetite. Nutr Rev 53, 1 ± 7. Drewnowski A (1997): Taste preferences and food intake. Ann. Rev. Nutr. 17, 237 ± 253. Drewnowski A & Popkin BM (1997): The nutrition transition: new trends in the global diet. Nutr. Rev. 55, 31 ± 43. Drewnowski A (1998): Energy density, palatability, and satiety: implications for weight control. Nutr. Rev. 56, 347 ± 353. Foltin RW, Fischman MW, Moran TH, Rolls BJ, Kelly TH (1990): Caloric compensation for lunches varying in fat and carbohydrate content by humans in a residential laboratory. Am. J. Clin. Nutr. 52, 969 ± 980. Gatenby SJ, Aaron JI, Jack VA, Mela DJ (1997): Extended use of foods modi®ed in fat and sugar content: nutritional implications in a freeliving female population. Am. J. Clin. Nutr. 65, 1867 ± 1873. Green SM, Burley VJ, Blundell JE (1994): Effect of fat- and sucrose containing foods on the size of eating episodes and energy intake in lean males: potential for causing overconsumption. Eur. J. Clin. Nutr. 48, 547 ± 555. Intense sweeteners and weight control A Drewnowski Green SM, Blundell (1996): Subjective and objective indices of the satiating effect of foods. Can people predict how ®lling a food will be? Eur. J. Clin. Nutr. 50, 798 ± 806. Harnack L, Stang J, Story M (1999): Soft drink consumption among US children and adolescents: nutritional consequences. J. Am. Dietet. Assoc. 99, 436 ± 441. Holt SHA, Brand Miller JC, Petocz P, Farmakalidis E (1995): A satiety index of common foods. Eur. J. Clin. Nutr. 49, 675 ± 690. Johnson SL, McPhee L, Birch LL (1991): Conditioned preferences: young children prefer ¯avors associated with high dietary fat. Physiol. Behav. 50, 1245 ± 1251. Kanders BS, Lavin PT, Kowalchuk MB, Greenberg I, Blackburn GL (1988): An evaluation of the effect of aspartame on weight loss. Appetite 11 (Suppl 1), S73 ± S84. Lavin JH, French SJ, Red NW (1997): The effect of sucrose- and aspartame-sweetened drinks on energy intake, hunger and food choice of female, moderately restrained eaters. Int. J. Obesity 21, 37 ± 42. Leibowitz SF, Kim T (1992): Impact of a galanin antagonist on exogenous galanin and natural patterns of fat ingestion. Brain. Res. 599, 148 ± 152. Levy AS, Heaton AW (1993): Weight control practices of US adults trying to lose weight. Ann Int Med 119, 661 ± 666. Lissner L, Heitmann BL (1995): Dietary fat and obesity: evidence from epidemiology. Eur. J. Clin. Nutr. 49, 79 ± 90. Louis-Sylvestre J, Tournier A, Verger P, Chabert M, Delorme B (1989): Learned caloric adjustment of human intake. Appetite. 12, 95 ± 103. Mattes R (1990): Effects of aspartame and sucrose on hunger and energy intake in humans. Physiol. Behav. 47, 1037 ± 1044. Mattes RD (1996): Dietary compensaton by humans for supplemental energy provided as ethanol or carbohydrate in ¯uids. Physiol. Behav. 59, 179 ± 187. Meiselman HR, Waterman D, Symington LE (1974): Armed Forces food preferences. Technical Report. Natick, MA: US Army Natick Development Center Parizkova J, Rolland-Cachera MF (1997): High proteins early in life as a predisposition for later obesity and further health risks. Nutrition 13(9), 818 ± 819. Poppitt SD, Prentice AM (1996): Energy density and its role in the control of food intake: evidence from metabolic and community studies. Appetite 26, 153 ± 174. Porikos KP, Hesser MF, Van Itallie TB (1982): Calorie regulation in normal-weight men maintained on a palatable diet of conventional food. Physiol. Behav. 29, 293 ± 300. Prentice AM, Poppitt SD (1996): Importance of energy density and macronutrients in the regulation of energy intake. Int. J. Obesity 20 (Suppl), S18 ± S23. Renwick AG (1994): Intense sweeteners, food intake, and the weight of a body of evidence. Physiol. Behav. 55, 139 ± 143. Rogers PJ, Blundell JE (1989): Separating the actions of sweetness and calories: effects of saccharin and carbohydrates on hunger and food intake in human subjects. Physiol. Behav. 45, 1093 ± 1099. Rogers PJ (1993): Appetite control and the use of intense sweeteners. Nutr 15. Rolls BJ (1986): Sensory-speci®c satiety. Nutr. Rev. 44, 93 ± 101. Rolls BJ, Hetherington M, Burley VJ (1988): The speci®city of satiety; the in¯uence of foods of different macronutrient content on the development of satiety. Physiol. Behav. 43, 145 ± 153. Rolls BJ, Hetherington M, Laster LJ (1988): Comparison of the effects of aspartame and sucrose on appetite and food intake. Appetite 11, (Suppl 1), S62 ± S67. Rolls BJ, Laster LJ, Summerfelt A (1989): Hunger and food intake following consumption of low-calorie foods. Appetite 13, 115 ± 127. Rolls BJ, Fedoroff IC, Guthrie JF, Laster LJ (1990): Foods with different satiating effects in humans. Appetite 15, 115 ± 126. Rolls BJ (1991): Effect of intense sweeteners on hunger, food intake and body weight: a review. Am. J. Clin. Nutr. 53, 872 ± 878. Rolls BJ, Kim-Harris S, Fischman MW, Foltin RW, Moran TH, Stoner SA (1994): Satiety after preloads with different amounts of fat and carbohydrate: implications for obesity. Am. J. Clin. Nutr. 60, 476 ± 487. Rolls BJ (1995): Carbohydrates, fats, and satiety. Am. J. Clin. Nutr. 61 (Suppl), S960 ± S867. Rolls BJ, Bell EA, Castellanos VH, Chow M, Pelkman CL, Thorwart ML (1999): Energy density but not fat content of foods affected energy intake in lean and obese women. Am. J. Clin. Nutr. 69, 863 ± 871. Rolls BJ, Kim S, Fedoroff IC (1990): Effects of drinks sweetened with sucrose or aspartame on hunger, thirst and food intake in men. Physiol. Behav. 48, 19 ± 26. Stubbs RJ, Prentice AM, James WP (1997): Carbohydrates and energy balance. Ann NY Acad Sci 819, 44 ± 69. Tordoff MG, Alleva AM (1990): Effect of drinking soda sweetened with aspartame or high-fructose corn syrup on food intake and body weight. Am. J. Clin. Nutr. 51, 963 ± 969. West DB, York B (1998): Dietary fat, genetic predisposition, and obesity: lessons from animal models. Am. J. Clin. Nutr. 67, 505S ± 512S. Willett WC (1998): Is dietary fat a major determinant of body fat?. Am. J. Clin. Nutr. 67(Suppl), 556S ± 562S. 763