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University of Wisconsin-Madison, Madison, Wisconsin
Address reprint requests to: Dale A. Schoeller, PhD, Professor, University of Wisconsin-Madison, 1415 Linden Dr., Madison, WI 53706. E-mail: dschoell{at}nutrisci.wisc.edu
| ABSTRACT |
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Methods: The effects and costs of overeating were estimated for men and women with a BMI of 22.5, 27.5, and 32.5 by conducting a Pubmed search for relevant literature combined with US statistics obtained from open Federal and other websites.
Results: Among fast food restaurants, the average upsized meal increases energy content of the meal from 927 to 1324 kcal at an added cost of $0.67. Because the regular meal is already 37% of a 2500 kcal diet, the extra energy of upsizing is likely to be in excess of need and thus potentially stored as 36 grams of added adipose tissue. This hypothesized weight gain predicts an average increase auto fuel cost by $0.05 for both men and women, maintenance food cost by $0.36 and $0.35 for men and women, respectively, and health care cost from $0.82 to $6.64.
Conclusions: These calculated costs exceed the value of upsized meals and may provide motivation to some consumers not to upsize their meals. The same rationale can be applied to other environments notorious for encouraging overeating. Thus, this information could be presented to individuals along with other more well publicized health risks and consequences during weight control counseling.
Key words: overeating, financial cost, subsequent energy intake, fast food restaurants
| INTRODUCTION |
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Numerous contributing factors are hypothesized to contribute towards obesity. Fundamentally, obesity must be caused by positive energy balance, for which energy intake exceeds energy expenditure. As of 2000, people in the United States are consuming greater energy per day than in 1971, without a proportionate rise in physical activity [6, 7]. Not surprisingly, during this time, the prevalence of obesity in adults rose from 14% to 30% [8]. Factors that increase energy intake include increased portion sizes and consumption of high-energy dense foods [912]. The opportunities to consume larger portions of energy-dense foods are enhanced by the increased frequency of eating outside the home particularly in light of the drastic increases in the amount of food served as a portion occurring in restaurants [13, 14]. A recent study found an increase in body mass index in individuals who eat fast food restaurant meals compared to those who do not [15]. These findings are dramatic considering it is currently reported that individuals average 78 visits per month to fast food restaurants [16]. Many fast food restaurants group their foods together (i.e. value meals) and then further offer the consumer a "bargain" by permitting upsizing to a larger portion. When people initially decide to order a larger meal deal, it appears to be a sound financial decision. The upsized value meal increases the energy content of the meal by 73% for only 17% more money; however, this may also contribute to overeating and weight gain.
The hidden financial costs associated with weight gain from upsizing a value meal may help convince people it is not a bargain. While information is available to people concerning the physical and medical consequences associated with increased portion sizes and overeating, additional financial costs for upsizing a meal have not been estimated [12, 14]. Knowledge of these hidden costs may help influence individuals to occasionally forgo upsizing and avoid overeating. Weight gain during times of overeating contributes to hidden costs; the ones calculated in this article are costs associated with increasing daily caloric needs, gasoline needs, and medical expenses. Herein, we estimate the non-advertised financial cost of upsizing a value meal.
| METHODS |
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Meal Size and Costs
Calculations were based upon nutritional information from major fast food restaurants that offered a comparable increase in both soft drinks and French fries as part of promotional value meal deals [1719]. The advertised price, obtained from the specific restaurant consumer service centers, to upsize a regular value meal to the largest size was averaged from the three fast food restaurants that fit the inclusion criteria. Similarly, the averaged caloric difference between value meals was based on the differences between the medium and largest soft drink and French fries based on information provided by the restaurants customer service center.
Calculation of Weight Gain
It was assumed that the regular value meal would adequately help meet the days caloric needs since it is already 37% of a 2500 kcal diet, and thus the additional calories from upsizing would be excess and likely cause positive energy balance. As reviewed by Schoeller, an average of 68% of excess calories consumed during overfeeding studies are stored as excess weight by the body [20]. Thus, to determine the amount of fat that would be stored in adipose tissue, the extra calories from the larger value meal were multiplied by 0.68 and then divided by 9.5 kcal/gram, the energy density of dietary fat, to determine the gram amount of fat stored.
Among adults, it has been shown when there is an alteration in body weight, secondary to energy imbalance, it is due to an addition or loss of approximately 80% fat mass (FM) and 20% fat free mass (FFM) [21]. Therefore, when there is an increase in FM, there is also an addition of FFM to help support the FM. Thus, the resulting calculated grams of FM was divided by 0.8 to estimate weight gain including the addition of FFM that comes along with addition of FM [21]. This final value was the weight used in calculations throughout the study, for a single bout of ordering the larger value meal.
Increased kcal Needs
It has been shown in various studies, including a longitudinal study, TEE increases with increase body weight [2225]. We, therefore, calculated the increase in energy needs to maintain the weight gain associated in the upsized meal. To quantify this increase in energy expenditure, the determined height of a typical American man and woman and calculated weight for each category were used in the Mifflin equation to determine average resting metabolic rate (RMR) [26, 27]. The Mifflin equation was used because of its validated accuracy in obese and nonobese populations [28]. A physical activity level (PAL) of 1.72 and 1.67 for men and women, respectively, was calculated by averaging physical activity levels for men and women ages 1874 [29]. TEE was estimated before and after the slight weight gain secondary to the single bout of eating a larger meal, by multiplying the Mifflin-determined RMR with the determined average PAL. To represent the increased number of calories necessary to meet the individuals increased energy needs for one year due to the weight gain incurred from overeating at a single meal, the difference between the two determined TEEs was multiplied by 365 days. In high-income countries, individuals spend on average 16 cents for every 100 kcal [30]. Thus, the increase in annual caloric needs was divided by 100 kcal and then multiplied by $0.16.
Gasoline Needs
An increase in weight in a vehicle decreases its gasoline efficiency; for every extra 100 pounds in a vehicle, there is a decrease of one mile per gallon (mpg) of gasoline [31]. Hence, the decrease in fuel efficiency, in regards to mpg of gasoline, can be calculated for the weight gain caused by overeating. As of year 2001, the average annual vehicle miles traveled per individual for all income brackets is 14,000 miles per year [32]. This was divided by 21, the average mpg of a lightweight vehicle, resulting in total gallons of gasoline per year purchased [33]. This value was then multiplied by the average cost of gasoline per gallon, $1.98 [34]. This resulted in the total cost of gasoline the average individual must buy for an entire year.
Medical Costs
Medical costs increase with BMI and weight gain [3538]. Yet, it is not clear whether medical costs increase linearly or not with increased weight. However, for small changes a linear relationship was assumed. The monetary cost of weight accrued from overeating at a single meal was determined using the calculated increase in medical costs from a longitudinal study and the body mass index (BMI, kg/m2) of the typical American man and woman [38]. Currently, health care expenditures for men of a normal weight BMI of 18.5 to 25, overweight BMI of 25 to 30, obese BMI of 30 to 35, and severe obesity BMI of 35 to 40 are $3915, $4561, $4738, and $6179, respectively. Health care expenditures for women of a normal weight BMI of 18.5 to 25, overweight BMI of 25 to 30, obese BMI of 30 to 35, and severe obesity BMI of 35 to 40 are $3991, $4365, $5085, and $5723, respectively. Thus, the increased medical care costs associated with the transition to the subsequent weight class (overweight, obese, or severely obese) was calculated for the three BMI categories. For instance, the normal BMI category was used as the starting point in determining weight gain necessary to bring the individual from a normal weight classification to the overweight classification. The weight gain from overeating a larger value meal was then multiplied by the total additional cost of being in the subsequent BMI category and then divided by the total necessary weight needed to bring the individual to a BMI of the subsequent BMI category. This end calculation determines the amount of increased medical expenditures the individual will have from overeating at a single meal.
| RESULTS |
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Weight Gained
The total amount of weight an individual will gain from a single upsized value meal is 36 grams of adipose tissue, assuming the 397 calories from the larger portion of the meal is excess calories.
Increased kcal Needs
Due to differences in initial body weights, the increased food costs are different for men and women. After eating a larger value meal, the estimated TEE will be 0.61 and 0.59 kcals/day for men and women, respectively. Over the course of a year, men and women will have to increase their food intake by 223 kcals and 217 kcals, respectively, to meet their increased energy needs. This can be interpreted as an increase in grocery expenses of $0.36 and $0.35, for men and women of all BMI categories, respectively, over the course of one year.
Gasoline Costs
Since the added weight gain is the same for both genders, the increased gasoline cost is the same. Instead of averaging 20.8 mpg, individual fuel efficiency would decrease by 0.001 mpg. To accommodate this loss in efficiency, a person must buy an extra 0.025 gallons of gasoline per year due to the 36 extra grams of body weight, or $0.05.
Medical Costs
When calculating medical cost increases due to weight gain, men with a BMI of 22.5, 27.5, and 32.5 had an increase of $2.98, $0.82, and $6.64, respectively. The associated medical cost increases due to weight gain in women with a BMI of 22.5, 27.5, and 32.5 was determined to be $2.03, $3.90, and $3.46, respectively.
Overall Results
When these three factors are taken into account, increased kcal needs, gasoline costs, and medical costs, along with the initial $0.67 upsizing cost, the total cost of weight gain from consuming a larger value meal for men with a BMI of 22.5, 27.5, and 32.5 are $4.06, $1.90, and $7.72, respectively. The total costs associated with women with a BMI of 22.5, 27.5, and 32.5 are $3.10, $4.97, and $4.53, respectively.
As reviewed, a calorie is a calorie despite the source, therefore, if there is excess energy intake in protein, carbohydrates, fat, or alcohol it will result in the calculated monetary debt [39]. Overall, regardless of specific macronutrient breakdown, it can be calculated, for every 100 kcals overeaten that are not compensated for, it will cost men with a BMI of 22.5, 27.5, and 32.5, $1.02, $0.48, and $1.94, respectively. It will cost women with a BMI of 22.5, 27.5, and 32.5, $0.78, $1.25, and $1.14, respectively. These results are summarized in Table 2.
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| DISCUSSION |
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Obesity prevalence is projected to rise from the current 30% to 40% by the year 2010. With this increase in obesity, mortality rate and chronic disease incidence will also most certainly increase affecting both quality of life and increasing the financial burden associated with obesity. This epidemic increases regardless of the wide exposure of health risks associated with obesity and overeating. It is already known that behavior is altered on an individual basis and may require multiple motivating factors per individual to initiate a change. Thus, it is beneficial to be able to provide as many potential physical and financial motivating factors to individuals that are contemplating dietary and lifestyle changes in an attempt to curb obesity overeating.
The central assumption of these calculations is individuals will not compensate for the excess calories during subsequent meals. It has been shown in short-term overfeeding studies that some individuals, mainly lean subjects, will compensate to an extent later in the day for the excess calories eaten [4042]. A degree of compensation has also been demonstrated in long term overfeeding studies [43, 44]. One such study involving four to six months of overeating, found the participants returned to their initial body weight within two and a half years [44]. Overall, some individuals will compensate for excess energy intake while others will not. There is support that lean adolescents and women subjects, who have never been obese, are more likely to compensate than overweight, obese, or previously-obese men and women [4042, 45].
Many other studies, however, do not support full compensation for overeating. The steady climb in the rate of overweight and obese adults in the United States, in fact, indicates that most individuals are overeating and failing to fully compensate for overeating. This is further demonstrated on a population basis due to the average yearly weight gain of 0.20.8 kg/year in adults [46]. When given a 4550% high fat meal individuals increase their energy intake by 15.4% compared to a 3035% medium fat meal [47]. In a separate study, larger portion sizes of high energy density entrees increased individuals energy intake by 56% with no compensation seen at the subsequent meal [48].
In a study specifically involving fast food restaurants, it was shown that both lean and overweight adolescents will overeat at a fast food meal [42]. However, the overweight adolescents were less likely to compensate throughout the day for the excess energy intake after a fast food meal. It has also been shown the elderly are more likely to overeat and fail to compensate [43].
Overeating is facilitated in fast food restaurant environments due to a modifiable lifestyle behavior of ordering larger portions than necessary. It is important to note, even if larger portion sizes are ordered, restaurant owners do not believe the meal is likely to be shared [49]. This is supported by research conducted by the American Institute for Cancer Research which found the majority of people report they eat all the food placed in front of them at restaurants [50]. This information along with the observation that if presented with a larger portion size, both lean and obese individuals will overeat, increases the likelihood of a positive energy balance for the day and thus a gain in weight [11, 12, 14, 51, 52]. This concept was enforced in a study showing that larger portion sizes offered at fast food restaurants resulted in overeating, especially larger portions of French fries and soft drinks [53]. Moreover, when larger portions of food and beverages are consumed, individuals did not compensate later in the day by decreasing their food intake by that many calories [54]. High energy density food items, like fast food meals, are found to encourage overeating more so than low calorie alternatives [9, 10, 55, 56]. This is especially relevant when eating outside the home because restaurant portion sizes have increased and the commonly offered items tend to contribute to a poor diet characterized by higher intakes in energy and fat, and lower in fruits and vegetables [5760].
When individuals gain weight, energy expenditure and hence maintenance energy requirements are increased. Cross sectional studies have shown that both resting metabolic rate and total energy expenditure are increased with increasing weight [2224, 27]. A longitudinal study has also shown that energy expenditure increases with weight gain [25]. This information on costs associated with overeating fast food restaurant meals is vital when considering most people do not go to a fast food restaurant and upsize their value meal only once a year. On average, men and women, of all income brackets, frequent fast food restaurants 7.8 times per month [16]. This number of visits and potential for repeated overeating would have a cumulative effect on financial costs if consumers failed to compensate for the overeaten kcals, which is supported by the average yearly weight gain of 0.20.8 kg/year in adults [46].
Fuel costs incurred by the overeating individual are the smallest and may appear inconsequential. However, it is important to demonstrate that body weight does affect fuel efficiency. It may not amount to enough money to effect how the individual views the impact. Yet the airline industry has had to revise their approach to policies such as baggage weight limits to account for the rising adiposity of their customers. It was reviewed, the airline industry had to purchase an additional 350 million gallons of jet fuel in 2000, which resulted in an additional $275 million in expenses due solely to the increased weight of passengers [61]. Thus, the increase may not concern the individual with their own overeating; however, with the increase in airline ticket prices they may be affected as a consumer.
For women, the hidden costs to upsize their value meal is 8% more than men. Women are particularly vulnerable to higher costs because less weight is necessary for women to bring them to the obese category since women tend to have greater initial BMIs than men. Also, an interesting note, when BMIs are used to evaluate health risk in men and women separately, women have greater health risks at a lower BMI than men in the employed population [62]. Hence, overeating at a meal effects the financial and health costs more for women than men.
A shortcoming of this evaluation is that we assume that costs can be calculated as a continuous smooth function when in fact almost everything is quantized. One does not purchase an extra gram of milk because their energy requirement increased a fraction of a kcal or develop a quarter of a case of type 2 diabetes secondary to obesity. Never-the-less, on a larger scale, someone will purchase an extra quart of milk because they use a little more each day and someone will develop type 2 diabetes. Thus, the costs for one person may increase substantially while those for another do not increase at all and the use of a per person average will miss this variance. Never-the-less, we elect to present the results on a per person basis to form the basis of a dietary educational tool as this is a limitation for individualizing any cost analyses.
Only increased caloric needs, gasoline, and medical expenses were used to determine financial costs associated with overeating. Others were considered and were not included for various reasons. We did not include personal hygiene products, cosmetics, and clothing. Soap and cosmetics were not included because we felt use of these products were highly variable due to individual application practices versus increased surface area due to weight gain. Purchased new clothing was not considered because weight gain was assumed to be slow and thus it is likely that normal "wear and tear" of clothing and changing styles would lead to new purchases before the weight increase would require new clothes.
| CONCLUSIONS |
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| ACKNOWLEDGMENTS |
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Received March 16, 2005. Accepted January 31, 2006.
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