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Recommendations for healthier hydration: addressing the public health issues of obesity and type 2 diabetes



Given the rapid increase in the prevalence of overweight, obesity, type 2 diabetes and other obesity-related conditions across the world, despite a plethora of evidence-based guidance for clinicians, innovative campaigns aimed at the general public and widespread government public health initiatives, it is clear that a novel approach is required. The importance of fluid intake has been overlooked in campaigns and guidelines and also in the clinical setting, where the question ‘what do you drink?’ is often omitted. It is a significant oversight that food pyramids and healthy-eating plates across the world omit fluids from their graphics and advice. While guidelines include recommendations on changes in physical activity and diet, often little or no advice is offered on the importance of healthier hydration practices, neglecting to highlight the contribution of beverages high in sugar, alcohol or additives. An interdisciplinary group of experts in medicine, nutrition, physiology and public health discussed issues surrounding healthy-hydration practices in March 2010 in Paris to create a consensus statement on hydration and gain of body weight and provide recommendations.


Given the rapid increase in the prevalence of overweight, obesity, type 2 diabetes and other obesity-related conditions across the world, despite a plethora of evidence-based guidance for clinicians, innovative campaigns aimed at the general public, and widespread government public health initiatives, it is clear that a novel approach is required. Many campaigns recognizing the importance of reducing sugar-sweetened beverages (SSB) have been launched in several countries. SSBs constitute a large percentage of energy consumed by youth [1]. Nevertheless, the importance of fluid intake has been often neglected in guidelines and also in the clinical setting, where the question ‘what do you drink?’ is often omitted.

It is a significant oversight that food pyramids and healthy-eating plates across the world omit fluids from their graphics and advice. In Mexico, guidance has been provided graphically, in the form of a ‘healthy beverage jug’ (or ‘pitcher’), which can be coupled with the ‘healthy-eating plate’ – the Mexican equivalent of a food pyramid [2]. In addition, the ‘5-Pasos por tu salud’ (‘5-steps for your health’) programme has been developed as a preventive approach to help modify lifestyle and dietary factors – in particular to reduce the caloric intake from SSB – in the Mexican population. In Indonesia, an earlier version of the food pyramid (‘tumpeng’), which only provided recommendations on the portion or serving size of each food group, has been revised to include recommended serving portions of various food groups and water. These guidelines recommend drinking approximately 2 L of water daily [3]. While guidelines include recommendations on changes in physical activity and diet, often little or no advice is offered on the importance of healthier hydration practices, neglecting to highlight the contribution of beverages high in sugar, alcohol or additives.

Several states in the United States through legislation, regulation or a combination thereof, have adopted laws regulating the availability of SSB in schools. However, state policies on sweetened beverages varied. Only six states have eliminated all beverages that contain caloric sweeteners in primary schools. Most restrict the size of the drink container [4]. However, such policies have encountered resistance from consumer groups, sugar producers, commerce chambers and the beverage industries. In the UK, under a new Responsibility Deal between industry and government, food manufacturers and retailers have pledged to make changes to improve the health of the population. In Mexico, following publication of studies of dietary patterns in adolescents [5], parents and consumer groups have become the major champions of the restriction or ban of caloric beverages from schools. An interdisciplinary group of experts in medicine, nutrition, physiology and public health discussed issues surrounding healthy-hydration practices in March 2010 in Paris to create a consensus statement on hydration and gain of body weight and provide recommendations. It was not intended to perform an exhaustive and systematic review of observational studies and interventions exploring the possible incidence of SSB and related sweetened beverages consumption on obesity and obesity-related diseases, since a number of recent reviews have been published on the topic [6, 7]. The major objective was, based on selected observations, to highlight the importance of including hydration in public health dietary recommendations.

The effect of sugar-sweetened beverages on weight-related conditions

Sugar-sweetened beverages

The mean sugar content of SSB in the United States is 10g 100g-1 (ranging from 4.5 to 14g 100g-1) [8]. SSBs represent the major source of dietary fructose. The introduction of high-fructose corn syrup (HFCS) in the 1970s in the United States has resulted in a 30% increase in total fructose intake in the last years [9, 10]. It was estimated that Americans ≥age 2 years ingest at least 132 calories per day from HFCS [11]. This parallels a remarkable increase in the rates of obesity and diabetes. During the last 30 years, there has been a noticeable increase in SSB consumption across the world [7]. SSB are now the primary source of added sugars in the American diet and contribute approximately 9% of total energy intake in both children and adults [12]. It is estimated that between 56 and 85% of schoolchildren consume at least one SSB every day [13], and one longitudinal analysis demonstrated that for each additional daily serving there was a 60% greater risk of becoming obese [14]. Furthermore, it has been shown that a positive energy balance of 120 kcal (500 kJ) per day – equivalent to about one serving of a SSB – may produce an approximate 50-kg (110-pound) increase in body mass over 10 years [13, 15]. The sugar energy content of one can of soda (12fl oz, 355 mL, 150 kcal, 630 kj) equals the energy expended by an 85 kg man who walks at a moderate pace for 30 min.

Therefore, any factor that increases energy intake or reduces energy expenditure has the potential to cause obesity over time [15]. When calorie-containing beverages are consumed before a meal, individuals do not eat less food to adjust for the calories consumed from the beverage. SSB also encourage dependence on and craving for sugar because of their sweetness [16, 17].

Although a number of observational studies support the hypothesis that SSB cause weight gain, debate still surrounds the epidemiological evidence for a causal link, due to a paucity of robust clinical trial data [6, 18, 19]. A number of epidemiological studies suggest that, in addition to excessive caloric intake, the low satiety of liquid carbohydrates provides a contributory mechanism [11, 14, 20-22]. It has been shown that, when a person increases intake of energy-rich liquid, this is not necessarily compensated by concomitantly reducing solid food consumption [7, 20, 23, 24]. Reduced gastric distension and faster transit times may mean that energy in fluids is less well ‘detected’ by the body [23]. In one cross-over study, daily consumption of a measured caloric amount of liquid soda resulted in significantly greater weight gain than daily consumption of an isocaloric solid carbohydrate load [24]. Furthermore, the large amount of rapidly absorbable carbohydrates from sugars and HFCS contained in some SSB may increase type 2 diabetes and cardiovascular risk – independent of obesity – due to a high glycaemic load, which can lead to inflammation, insulin resistance and impaired β-cell function [22]. Fructose has been implicated in the pathogenesis of metabolic syndrome and non-alcoholic fatty liver disease [25]. The liver is the major site of fructose metabolism. Hepatic metabolism of fructose is very different from that of glucose and is known to increase noticeably de novo lipogenesis in liver [10, 26]. Fructose stimulates, while fat inhibits, hepatic very-low-density lipoprotein triacylglycerol secretion [27]. Females may be protected against fructose-induced hypertriglyceridaemia because of a lower stimulation of de novo lipogenesis and a lower suppression of lipid oxidation [28]. Consuming fructose-sweetened beverage has been shown to increase visceral adiposity, hepatic lipogenesis and decrease insulin sensitivity [29]. Fructose ingestion in a drink stimulates a sustained increase in blood pressure [30]. Although it is difficult to extrapolate long-term effects from acute responses, diets that include repeated fructose loads might contribute, over time, to the changes associated with metabolic syndrome even without increasing body weight and to increased cardiovascular risk. Moreover, metabolic damage is not limited to obesity-related disorders and fructose exerts specific biochemical effects beyond its caloric equivalent [31, 32].

Fruit juices

It is not widely recognized, or understood, that fruit juices can contain high amounts of sugar [20, 33, 34]. It is important to make a clear distinction between ‘juice drinks’ which contain a minimum of fruit juice and added sugar from the ‘100 per cent fruit juice’ with no added sugar. Although fruit juice can form an integral part of a healthy, balanced diet when consumed in moderate amounts, excessive consumption may contribute to weight gain and an increased risk of diabetes [34]. Daily intake of some fruit juice drinks, such as apple, grapefruit or cranberry (which are sweetened with sugar to make them more palatable), has also been shown to increase the risk of kidney stones in individuals with normal/healthy kidneys [35], as it has with cola-flavoured SSB in individuals with newly-diagnosed chronic kidney disease [36]. Patients with kidney stones are routinely advised to increase their fluid intake to reduce the risk of stone recurrence; however, evidence suggests that the type of fluid may be as important as the amount, particularly in women.

Non-nutritive beverages

‘Diet’, ‘light’ or ‘zero-calorie’, also called non-nutritive sweeteners (NNS) are often promoted as low/no-calorie alternatives to SSB. These drinks contain at least one non-caloric sweetener (e.g. acesulphame-K, aspartame, cyclamate, neotame, saccharin, sucralose and rebaudioside A, stevia) that provide a sweet taste without any calories [21, 37]. Gram for gram, these artificial sweeteners are much sweeter than sugar [21] and are titrated to obtain a predetermined level of sweetness. Although such drinks represent a marked reduction in caloric intake, and potential reduction in health risk, they could present disadvantages compared to drinking water with regard to general and dental health [38]. Recent data from epidemiological studies in humans reveal a positive association between consumption of NNS and weight gain [16]. Several potential mechanisms are hypothesized. Dissociating sweetness from calories could interfere with mechanisms controlling body homeostasis. By changing the intestinal environment, NNS could also affect the microbiota in turn triggering inflammatory processes associated with metabolic disorders and obesity risk. Interaction of NNS with gut receptors which are similar to sweet-taste receptors of the mouth, could affect absorptive capacity and glucose homeostasis. Whether NNS are metabolically inactive, as previously assumed, is unclear. Further research on potential NNS effects on human metabolism is warranted [39]. Aspartame specifically continues to be a controversial NNS; the European commission has requested a re-evaluation of its safety by the European Food Safety Authority (EFSA). Following its call for data, EFSA was given access to over 600 data sets for use in its full re-evaluation of aspartame, which is scheduled for completion in 2012.

Recent research suggests that intense sweetness in beverages may condition people to have a preference for sweet tastes [23, 40]. Individuals with heightened reward sensitivity (e.g. sweetness) may be at risk of palatability-driven feeding, which preliminary evidence suggests may be linked to increased food intake and body mass index (BMI) [41, 42]; however, further research is required. A recent observational study of American participants from different ethnicities reported that daily consumption of NNS was associated with an increased risk of developing two metabolic syndrome components – weight gain and impaired glucose control – and developing type 2 diabetes [43], confirming the findings of other studies on the development of the metabolic syndrome. Diet soda (P trend ≤ 0.001) was adversely associated with incident metabolic syndrome whereas dairy consumption (P trend = 0.006) was beneficial. The diet soda association deserves further studies [44].

Thus, current literature suggests that excessive or habitual consumption of SSB, fruit juices and also non-caloric beverages may have deleterious effects on health [45]. While more research is required, it is important to address a current lack of information and misunderstanding among the general public on how best to make informed, healthy beverage choices, including drinking more water.

Other effects on health

Effects on the gastrointestinal tract

Different beverages affect stimulation of gastrointestinal hormones differently [45]. Certain molecules present in NNS, bind to receptors in the gastrointenstinal tract altering physiological responses. Several enteroendocrine cell types throughout the gastrointestinal tract contain receptors similar to those previously identified in taste buds on the tongue [46]. These ‘taste’ receptor molecules may participate in the functional detection of organic nutrients, but also of chemical xenobiotics and harmful substances in the gut lumen [47]. Such receptors recognize natural sugars such as sucrose and glucose but also artificial sweeteners [48], and may be involved in the control of food intake via the activation of gut-brain neural pathways. The physiological role of the taste receptor machinery in gut endocrine cells remains to be clarified [49].

Effects on dental caries

Evidence from observational studies, conducted in a number of different countries, has confirmed that high SSB intake increases the risk of developing dental caries, particularly in children [50-61]. Similar findings are reported in adults, however, the number of studies is limited [62-66]. It is widely accepted that acids in SSB and NNS play a major role in the development of dental erosion. Evidence from observational studies in children suggests that consumption of SSB is associated with an increased risk of dental erosion [67-70]. A recent cross-sectional study in Brazil showed that school children consuming one or more SSB a day had a 70% higher risk of dental erosion than those with lower or no intakes (four times per week or less) [71]. An additional study, following approximately 1150 English children from the age of 12 to 14 years, showed that high consumption of carbonated SSB was a strong predictor of the amount of dental erosion observed at the age of 14. The risk of erosion was increased by approximately 50% for each additional SSB intake per day [68]. Diabetes also has a detrimental effect on oral health and is linked to the development of gingivitis and periodontal disease [72, 73]. While it is well established that diabetes is a risk factor for periodontitis (via an elevated inflammatory response to periodontal microflora), authorities have suggested that inflammatory periodontal disease may increase insulin resistance in a way similar to obesity, thereby impairing glycaemic control [72, 74]. Thus, increasing evidence suggests that high SSB intake is a risk factor for dental caries and erosion, and suggests that intake should be limited, and at least partially replaced by healthier alternatives. Physicians and oral health providers should be aware of the potential negative impact on heath and of the possible bidirectional relationship of SSB, periodontal disease and diabetes.

Effects on cognitive performance and mood

Severe dehydration (i.e. over 13, 24 and 37 h of fluid restriction) is known to exert detrimental effects on cognition performance in adults. Ability to concentrate and alertness were noticeably reduced [75]. In adult men, mild dehydration without hyperthermia has been shown to degrade specific aspects of cognitive performance and to promote adverse changes in vigilance and working memory [76]. In adult women, one recent publication demonstrated that mild dehydration decreased alertness but increased sleepiness, fatigue and confusion [77]; whereas a second publication demonstrated that mild dehydration degraded mood, increased the perception of task difficulty, lowered concentration and increased headache symptoms [78]. Children, with their higher surface area-to-mass ratio, reduced body cooling pathways and sensitivity of thirst detection mechanisms, are considered to be at higher risk for dehydration than adults. In infants, dehydration is associated with confusion and irritability [79]. Results need to be confirmed by future research and studies of alterations of cognitive performance require deeper attention. In a study conducted in UK, free access to drinking water in class was associated with improved total fluid intake [80]. In view of such results, it is clear that primary schools should promote water drinking in class.

Drinking safe and sufficient water as a means of healthy hydration should be emphasized as a cornerstone in preventing and managing overweight and obesity in the context of serious chronic disease.

Water, a vital nutrient, has numerous critical roles in the body as the main constituent of cells, tissues and organs [81]. However, water is often forgotten in dietary recommendations although the physiological basis of hydration is well known [82, 83]. Water, quantitatively important and most essential nutrient, has no generally promoted dietary reference intake values. It has no calories and contains no sugars.

Although early studies suggested the benefits of large fluid intake in patients (particularly those with chronic kidney diseases), there has been a rising furor about the exhortation ‘to drink at least eight glasses of water per day’. Some authors have questioned this claim and mentioned that, there is no clear evidence of benefit from drinking increased amounts of water [84, 85]. However, there is no evidence to show that drinking such a level of fluid might be bad for health. Some other have also decried this practice [86, 87] while they have not provided striking arguments to demonstrate that there no clear evidence of a lack of benefit. There is recent evidence that increased fluid intake may be beneficial in preserving kidney function [88, 89].

It is important to establish if replacement of caloric beverages with non-caloric beverages (water or diet beverages) could have public health significance. It may be a simple strategy for promoting weight reduction on the long term. Recent studies have shown that increasing water intake and reducing carbonated SSB consumption is effective at preventing excessive weight gain in schoolchildren [90-93]. A randomized, controlled cluster trial in German schoolchildren found a significant 31% reduction in risk of overweight after a 12-month programme of promoting increased water consumption alone (e.g. by providing water fountains, refillable water bottles and structured classroom lessons on the hydration needs of the body), compared with control groups [93]. A UK study of similar design focused on reducing carbonated drink consumption, which also included the promotion of drinking more water. Compared with the control group, there were significant reductions in carbonated drink consumption and in the proportion of overweight and obese children in the intervention groups after 12 months [90]. Similarly, a Brazilian interventional study reported that decreasing SSB and fruit juice intake reduced BMI among overweight children (−0.4 kg m−2 in those participating in a healthy lifestyle educational programme vs. −0.2 kg m−2 in the control group [P = 0.11]); this difference was statistically significant among girls (P = 0.009) [92]. Researchers found in middle-aged and older adults that the addition of two glasses of water consumed before meals resulted in a greater loss of weight when compared with a group who did not drink water. When combined with a hypocaloric diet, consuming 500 mL water prior to each main meal lead to greater weight loss than a hypocaloric diet alone in middle-aged and older adults [94]. A recent study performed in obese and overweight adults shifted from SSB to water is in favour of benefits from water intake for weight control. An average weight loss of 2% to 2.5% was observed [95].

While such studies have reported positive results, further action is required at the public health and health care provider levels, to elicit change among the general population. In anticipation of the potential benefits of healthy-hydration advice, countries such as Mexico, the United States and Indonesia, have proposed public-health models [96-99] and initiated healthy-hydration guidance.

Recommendations for healthy hydration

This Expert Working Group believes that awareness of the need for healthy-hydration advice, within the context of dietary and lifestyle guidelines for the management and prevention of existing public health problems such as overweight and obesity should be better emphasized. Occasional or moderate consumption of SSB in addition to a healthy, balanced diet is not an issue of contention. Indeed, for fruit juices in particular, their relatively efficient provision of key vitamins should be recognized. However, public health bodies and health care professionals in the frontline, should be aware of the potential detrimental effects of excessive or habitual consumption on long-term health, particularly in children and adolescents. Healthcare professionals are well positioned to identify and promote behavioural changes which decrease SSB consumption and encourage water intake, deciphering misleading marketing messages which encourage children and parents to consume drinks in contradiction to public health advice.

In recognition of the increasing incidence of obesity and type 2 diabetes, the group recommends that both public health providers and practising health care professionals provide the general population with state-of-the-art educational information and guidelines that encourage informed decisions about changing drinking behaviour. Healthy adults regulate water balance with precision, while young infants and elderly people are at greater risk of dehydration [82]. Simple easy-to-understand healthy-hydration messages should be communicated to the general public and to the following six specific groups.

Teachers and schoolchildren

Many studies of school policies directed at SSB consumption have been published and summarized in a recent review of literature [1]. Schools, pre-school and after-school programmes are important settings in which to influence dietary intake and provide nutritional advice to schoolchildren, their parents or caregivers. While it has been reported that behaviour can be influenced by interventional programmes in educational settings, often such programmes are not of sufficient magnitude or duration to cause a significant improvement or alter the prevalence of obesity in this setting. The Expert Working Group recommends that high calorie SSB be replaced by healthier beverages low in calories; water being the best choice. Ideally, policies encouraging restriction of SSB availability in school must be supported (i.e. restriction of vending machines and snack bars, setting up of water fountains and substantial tax increases). Additional research and obesity prevention and management programmes are warranted, should be integrated into community-based plans and should focus on behavioural change within the whole community [99, 100]. Primary schools should promote water drinking in class. Schools contribute to a small portion of youth consumption [101] and it is important to diminish SSB availability from other sources, particularly in the home environment.

Parents and children

Parents should be aware of the importance of imparting healthy dietary advice and healthy drinking habits to their children. Recent efforts have been made to limit SSB consumption at schools but a recent study reported that US children aged 2 to 18 years consumed the majority of SSB in the home (55% to 70% depending on age) [102]. Among ethnicities, striking disparities in consumption trends of certain SSB have been reported [103-105]. These observations indicate the complexity in determining strategies for reduction of beverage calories and the importance of parental care. Educating parents to instil health drinking habits in children remains an important educational challenge. SSB intake by kids must be encouraged to be the lowest with objectives towards no intake. Replacing SSB with drinking water is associated with lower energy intake and is not negated by compensatory increase in other food or beverages [106]. Moreover, reducing the number of hours spent in front of a television or computer may also be a key intervention in this setting [100] and may help to discourage sedentary behaviour within the home, which has been shown to be correlated with an over-consumption of SSB and energy-dense foods [107, 108]. Children should be encouraged to participate in 1 h of physical activity and limit their screen time to less than 2 h every day [109, 110].

Adults in the workplace

A number of dietary intervention programmes have been conducted in the workplace, using both educational and environmental-based strategies, with mixed results {Hider, 2001 #46}. Some studies showed no impact [111], whereas others reported significant but small benefits of educational and environmental interventions on improving dietary habits [112, 113]. While the workplace is an important setting in which to reach adults (particularly men, who are invariably more difficult to reach through school or community-based programmes), the impact of interventional programmes to date have been relatively small {Hider, 2001 #46; (100)}. This suggests that other interventional approaches should be attempted and evaluated. The public health sector has a particularly important role to play. Recommendations must be focused towards healthy drinking policies focusing on promotion of drinking water. Moreover, easier access to water in vending machines or free access to sensor-based automated drinking fountains must be privileged.

Pregnant and lactating women

Pregnant and breastfeeding women should be encouraged to increase their intake of water and other fluids to meet their bodies' requirements [114]. Breastfeeding women can produce approximately 750 mL of breast milk every day and guidelines suggest that breastfeeding mothers should drink an extra 700–1000 mL water daily during the first 6 months of breastfeeding to compensate for fluid loss [115].

Individuals who participate in regular recreational exercise or sports (e.g. members of leisure centres/gyms)

Loss of body fluids containing water and electrolytes during exercise occurs mostly by sweating. Sweat rates during physical activity or a sporting event will vary according to a number of factors, including the size of the athlete and his or her degree of acclimatization, environmental conditions, the intensity of exercise and the clothing worn. Individuals who participate regularly in recreational sports and/or exercise are dehydrated during exercise and drink at a rate according to their perceived thirst, which barely replaces two-thirds of their fluid losses [116, 117]. Dehydration during exercise increases perceived effort [118]. Conversely, replacing fluids during prolonged exercise enhances physical performance and lowers perception of effort [119-121]; also, those participating in endurance sports who are properly hydrated take longer to reach exhaustion [116]. Improving hydration status by ad libitum consumption of water can enhance performance in young children exercising in the heat [122]. It should be noticed that fluid loss is strongly modulated by ambient temperature and fitness level. For example the sweat rate of well-trained individuals is higher than that of sedentary persons. For moderate intensity recreational exercise lasting 1 h or less, consumption of sugar in fluids or solid food is not required; the body's fuel reservoirs provide ample energy for such activity [123]. However, debate exists regarding the quantity of fluid that should be consumed during exercise, especially in children who may be at greater risk of dehydration [124, 125]. While some sport authorities recommend that children aged 15 years and above and adults should drink between 400 and 800 mL [126] or 600 and 1000 mL of fluid per hour to optimize exercise performance [127], others advise ‘drinking to thirst’ in order to avoid consuming a very large volume of water causing exercise-induced hyponatremia [128]. This disorder is uncommon (incidence of approximately 1 in 1000 individuals who compete in mass participation events), however, and usually occurs only when exercise lasts longer than 4 h.

Elderly people

Adults aged 65 years or more frequently experience fluctuations in fluid balance and dehydration [129] because the body's ability to concentrate urine and conserve water is impaired with advanced age [130]. Another consequence of increasing age is a decreased perception of thirst [131, 132]. Therefore, it is important that elderly individuals and their caregivers receive educational advice. Regular monitoring of hydration state and active rehydration are needed to prevent dehydration in this specific population [45, 133].


Given the rapid increase in the prevalence of overweight, obesity and type 2 diabetes across the world, it is now essential that public health authorities and health care providers impart evidence-based guidance and advice to the general public, to prevent overweight and obesity-related health care costs and societal burdens from escalating. The Expert Working Group calls for better hydration practices to be more widely adopted, specifically for all management guidelines regarding prevention and management of overweight and obesity. Further, all national ‘food pyramids’ and ‘portion plates’ should demonstrate what drinks should be consumed as part of a healthy balanced diet.

Expert Working Group Consensus recommendations for providing healthy-hydration advice

Increase healthcare provider education and public awareness of (i) the importance of drinking ample safe water, within the context of a healthy, balanced diet and (ii) the detrimental effects of over-consumption of SSB and NNS on long-term health.

  1. To achieve this goal and to ensure adoption by the general public, increasing awareness of the current obesity epidemic is paramount, both at a national and a regional level. Revise current dietary guidelines to include evidence-based advice on healthy hydration within the context of dietary and lifestyle modifications.
  2. Revise national nutrition guidelines to emphasize the importance of water as a macronutrient and to include it within the food pyramid as recently performed [99].
  3. Newly-revised guidelines should be simple, effective and include easy-to-remember targets for each group of individuals. For example, guidelines should advise normal adults to drink approximately 2 L of water per day [115, 134]. Recommendations about healthy eating and regular exercise practice must be associated to hydration guidelines.
  4. Water intake should be emphasized during physical activity, sweating and when living in hot and cold environments.
  5. Conduct new research to identify the daily water needs of specific groups (e.g. pregnant and lactating women, the elderly, etc). Longitudinal studies should also be extended to different populations (different countries, different socioeconomic levels and different age groups) to optimize hydration procedures.

Author disclosures

The authors declare, as Expert Working Group members, to serve as paid consultants for the Hydration for Health Initiative sponsored by Danone Research, France. Additionally, Professors Lawrence E. Armstrong and Simon Barquera receive grant funding from Danone Research, France.