A rapid beverage intake questionnaire can detect changes in beverage intake

Attention on beverage intake, specifically sugar-sweetened beverages (SSB), has increased in recent years. A brief valid, reliable and sensitive assessment tool for quantifying beverage consumption and determining its influence on weight status could help to advance research on this topic. The valid and reliable 15-item beverage questionnaire (BEVQ-15) estimates mean daily intake of water, SSB and total beverages (g, kcal) across multiple beverage categories. Objective: to determine the ability of the BEVQ-15 to detect changes in beverage intake over time. Participants (n = 70; age = 37 ± 2 yr; BMI = 24.5 ± 0.4 kg/m²) underwent two randomly assigned 30-day periods (intervention, increased water and fruit juice consumption; control, increased solid fruit consumption), with a 30-day washout phase between feeding periods. The BEVQ-15 was administered at the beginning and end of each period. Reliability was assessed by Pearson's correlations, paired sample t tests and Cronbach's alpha. Paired sample t tests and repeated measures ANOVA were used to evaluate sensitivity to change. Sixty-nine participants completed all study sessions. Reliability was acceptable for most beverages (range: R² = 0.52–0.95, P < 0.001), but not for energy drinks. Increases in water (g), juice (kcal, g) and total beverage (g) were detected during the intervention period (P < 0.001); no changes in these variables were detected in the control period. The BEVQ-15 demonstrates the ability to detect changes in beverage intake over time. This brief (~ 2 min), self-administered, valid, reliable and sensitive beverage intake assessment tool may be used by researchers and practitioners who evaluate and intervene upon beverage intake patterns in adults.     

Carbohydrate intake during exercise and performance

It is generally accepted that carbohydrate (CHO) feeding during exercise can improve endurance capacity (time to exhaustion) and exercise performance during prolonged exercise (>2 h). More recently, studies have also shown ergogenic effects of CHO feeding during shorter exercise of high intensity ( approximately 1 h at >75% of maximum oxygen consumption). During prolonged exercise the mechanism behind this performance improvement is likely to be related to maintenance of high rates of CHO oxidation and the prevention of hypoglycemia. Nevertheless, other mechanisms may play a role, depending on the type of exercise and the specific conditions. The mechanism for performance improvements during higher-intensity exercise is less clear, but there is some evidence that CHO can have central effects. In the past few years, studies have investigated ways to optimize CHO delivery and bioavailability. An analysis of all studies available shows that a single CHO ingested during exercise will be oxidized at rates up to about 1 g/min, even when large amounts of CHO are ingested. Combinations of CHO that use different intestinal transporters for absorption (e.g., glucose and fructose) have been shown to result in higher oxidation rates, and this seems to be a way to increase exogenous CHO oxidation rates by 20% to 50%. The search will continue for ways to further improve CHO delivery and to improve the oxidation efficiency resulting in less accumulation of CHO in the gastrointestinal tract and potentially decreasing gastrointestinal problems during prolonged exercise.     

Impact of fluid restriction and ad libitum water intake or an 8% carbohydrate-electrolyte beverage on skill performance of elite adolescent basketball players

Twelve adolescent athletes underwent, in a crossover-design study, 3 separate 90-min training sessions in the following conditions: no fluid ingestion allowed (NF), ad libitum ingestion of water (W), and ad libitum ingestion of a commercial 8% carbohydrate-electrolyte sports beverage (CSB). After each session athletes performed a set of basketball drills (2-point, 3-point, and free-throw shootout, suicide sprints, and defensive zigzags). Body weight (before and after sessions), rating of perceived exertion (RPE), urine color, and beverage acceptability were determined in each session. Athletes also completed a survey about their knowledge and behaviors regarding hydration and fluid replacement. The percentage of weight loss was significantly higher in NF (2.46% ± 0.87%) than in the other 2 conditions (W, 1.08% ± 0.67%, p = .006; CSB, 0.65% ± 0.62%, p = .001) but also higher in W than CSB (p = .012). RPE was higher in NF (16.8 ± 1.96) than in the W (14.2 ± 1.99, p = .004) and CSB (13.3 ± 2.06, p = .002) trials. Athletes' fluid intake was positively correlated with proper self-reported behaviors (r = .75, p = .005) and knowledge (r = .76, p = .004) about fluid and hydration. In conclusion, fluid restriction during exercise was associated with a greater level of dehydration and increased perceived exertion but had no impact on basketball performance compared with ad libitum drinking of water or a CSB. Athletes with more knowledge about hydration and better self-reported hydration behaviors ingested more fluids during training sessions.     

Impact of nutrient intake timing on the metabolic response to exercise

Effects of nutrient intake timing and exercise on carbohydrate (e.g. insulin sensitivity), protein (muscle protein synthesis), and fat (circulating triacylglycerols) metabolism are reviewed in this paper. Altered nutrient intake timing relative to exercise can modulate the metabolic response, which is relevant for individuals seeking to use exercise to enhance health.     

Effect of caffeine intake on pain perception during high-intensity exercise

Caffeine has been shown to reduce leg-muscle pain during submaximal cycle ergometry, as well as in response to eccentric exercise. However, less is known about its analgesic properties during non-steady-state, high-intensity exercise. The primary aim of this study was to examine the effect of 2 doses of caffeine on leg pain and rating of perceived exertion (RPE) during repeated bouts of high-intensity exercise. Fifteen active men (age 26.4 ± 3.9 yr) completed 2 bouts of 40 repetitions of "all-out" knee extension and flexion of the dominant leg at a contraction velocity equal to 180°/s. Before each trial, subjects abstained from caffeine intake and intense exercise for 48 hr. Over 3 days separated by 48 hr, subjects ingested 1 of 3 treatments (5 mg/kg or 2 mg/kg of anhydrous caffeine or placebo) in a randomized, single-blind, counterbalanced, crossover design. Leg-muscle pain and RPE were assessed during and after exercise using established categorical scales. Across all treatments, pain perception was significantly increased (p < .05) during exercise, as well as from Bout 1 to 2, yet there was no effect (p > .05) of caffeine on pain perception or RPE. Various measures of muscle function were improved (p < .05) with a 5-mg/kg caffeine dose vs. the other treatments. In the 5-mg/kg trial, it is plausible that subjects were able to perform better with similar levels of pain perception and exertion.     

Gastrointestinal discomfort during intermittent high-intensity exercise: effect of carbohydrate-electrolyte beverage

This study investigated whether different beverage carbohydrate concentration and osmolality would provoke gastrointestinal (GI) discomfort during intermittent, high-intensity exercise. Thirty-six adult and adolescent athletes were tested on separate days in a double-blind, randomized trial of 6 % and 8 % carbohydrate-electrolytes (CHO-E) beverages during four 12-min quarters (Q) of circuit training that included intermittent sprints, lateral hops, shuttle runs, and vertical jumps. GI discomfort and fatigue surveys were completed before the first Q and immediately after each Q. All ratings of GI discomfort were modest throughout the study. The cumulative index for GI discomfort, however, was greater for the 8 % CHO-E beverage than for the 6 % CHO-E beverage at Q3 and Q4 (P < 0.05). Averaging across all 4 quarters, the 8 % CHO-E treatment produced significantly higher mean ratings of stomach upset and side ache. In conclusion, higher CHO concentration and osmolality in an ingested beverage provokes stomach upset and side ache.     

The acute effects of dairy calcium intake on fat metabolism during exercise and endurance exercise performance

The purpose of this study was to test the effect of acute dairy calcium intake on exercise energy metabolism and endurance performance. Trained female runners completed two trials. Each trial consisted of a 90-min glycogen depletion run followed by a self-paced 10K time trial, conducted one hour after consumption of a high dairy (500 mg Ca+2) or low dairy (80 mg Ca+2) meal. During the 90-min run, blood samples and respiratory gases were collected. No treatment main effects of acute dairy intake were found for respiratory exchange ratio (RER), calculated fat oxidation, lactate, glycerol, or 10K time. Following this protocol, acute dairy calcium intake did not alter fat utilization or endurance performance in trained female runners.     

The effect of temperature and humidity levels in a protective mask on user acceptability during exercise

Subjective and physiological responses were obtained from six subjects wearing a ventilated face mask while exercising (3.8 met) for 15 min on a bicycle ergometer. Different combinations of ambient air temperatures (7 degrees, 16 degrees, 25 degrees C) and mask air temperatures (22 degrees, 27 degrees, 33 degrees C) were studied together with two different air humidities inside the mask (61% and 86% RH). Control experiments were performed without the mask at the same ambient temperatures. Skin temperatures, heart rates and skin wettedness were monitored during exercise. The subject's acceptance of the mask and thermal environment, thermal sensation, sensations of discomfort, sweating and skin wettedness, and their judgment of the work of breathing were assessed at the end of the 15 min exercise period. The acceptance of both the ambient thermal environment and of the thermal microclimate in the mask primarily was determined by the ambient air temperature, but it was influenced by the air temperature and humidity inside the mask. At ambient temperatures of 7 degrees C and 25 degrees C, the acceptance of the thermal work conditions decreased. In the warm environment a mask air temperature less than or equal to 27 degrees C was 100% acceptable and increased the acceptance of thermal environment. In the cool environment, a mask air temperature greater than or equal to 27 degrees C was 100% acceptable. The humidity content of the mask air was only important when the mask air was warm. Warm humid air significantly decreased acceptance of the mask conditions.     

耐力性运动中补糖对自行车运动员IL-2的影响

目的通过给耐力自行车运动员在运动过程中补充8％低聚糖饮料，观察NK细胞的数量变化以及IL-2的活性变化，并探讨其机制。方法10名自行车运动员以70％的摄氧量进行功率车运动1h，运动前、运动后即刻、运动后2h以及运动后4h采集静脉血，测试机体NK细胞数量和IL-2的活性。结果在耐力性运动中补糖可以增加NK细胞的数量，增强IL-2的活性。结论在耐力性运动中补糖可以增加能量供应，并帮助机体免疫系统的维持。     

Effects of calorie and fluid intake on adverse events during hemodialysis.

PURPOSE: To investigate the incidence of adverse events during hemodialysis treatments as a function of calories and fluid intake. METHODS: The study period was August 3-26, 1999. Hemodialysis visits were studied. Twenty-three patients receiving hemodialysis during the 2nd shift on Tuesday, Thursday, and Saturday were studied. A total of 166 hemodialysis patient visits were studied. Data collected included: amount of fluid and food consumed, blood pressure levels, and mannitol use during each hemodialysis treatment; and any symptoms that occurred either during or after the dialysis treatment (hypotension, nausea, vomiting, diarrhea, cramping, and access problems). RESULTS: Using regression analysis, calories and fluids were strong predictors of both hypotension (P =.003) and mannitol use (P =.000), but not of cramping or access problems. Patients were 3 times more likely to have hypotension if taking any fluids (P =.011). Patients consuming >200 calories were 2 times as likely to have hypotension (P =.058). Patients were 5 times more likely to use mannitol if taking any fluids (P =.005). Mannitol use increased significantly (P =.001) with those patients consuming >200 calories. CONCLUSION: Patients who ate more than 200 calories and consumed more than 200 mL of fluid during hemodialysis had an increased incident of hypotensive events and increased use of mannitol.     

Effect of carbohydrate ingestion during exercise on post-exercise substrate oxidation and energy intake

Thirteen physically active, eumenorrheic, normal-weight (BMI < 25 kg/m2) females, aged 18-30 years, completed 4 experimental conditions, with the order based on a Latin Square Design: (a). CHO/Ex: moderate-intensity exercise (65% VO2peak) with a net energy cost of approximately 500 kcals, during which time the subject consumed a carbohydrate beverage (45 g CHO) at specific time intervals; (b). CHO/NoEx: a period of time identical to (a). but with subjects consuming the carbohydrate while sitting quietly rather than exercising; (c). NoCHO/Ex: same exercise protocol as condition (a.) during which time subjects consumed a non-caloric placebo beverage; and (d). NoCHO/NoEx: same as the no-exercise condition (b). but with subjects consuming a non-caloric placebo beverage. Energy expenditure, and fat and carbohydrate oxidation rates for the entire exercise/sitting period plus a 90-min recovery period were determined by continuous indirect calorimetry. Following recovery, subjects ate ad libitum amounts of food from a buffet and were asked to record dietary intake during the remainder of the day. Total fat oxidation (exercise plus recovery) was attenuated by carbohydrate compared to placebo ingestion by only approximately 4.5 g. There was a trend (p =.08) for a carbohydrate effect on buffet energy intake such that the CHO/Ex and CHO/NoEx energy intakes were lower than the NoCHO/Ex and NoCHO/NoEx energy intakes, respectively (mean for CHO conditions: 683 kcal; NoCHO conditions: 777 kcal). Average total energy intake (buffet plus remainder of the day) was significantly lower (p <.05) following the conditions when carbohydrate was consumed (CHO/Ex = 1470 kcal; CHO/NoEx = 1285 kcal) compared to the noncaloric placebo (NoCHO/Ex =1767 kcal; NoCHO/NoEx = 1660 kcal). In conclusion, in young women engaging in regular exercise, ingestion of 45 g of carbohydrate during exercise only modestly suppresses total fat oxidation during exercise. Furthermore, the ingestion of carbohydrate with or without exercise resulted in a lower energy intake for the remainder of the day.     

The timing of fluid intake during an Olympic distance triathlon

Seven highly trained male triathletes, aged 18 to 35 years, were tested during two simulated Olympic distance triathlons to determine whether run performance was enhanced when consuming 177 ml of water at 8, 16, 24, and 32 kilometers (Early Trials) compared to consumption at 10, 20, 30, and 40 kilometers (Late Trials), during the cycling segment of the triathlon. Swim times for 1500 m were similar between trials; 40-km cycling times were approximately 10 s faster during the Late Trials; however, 10-km run times were faster during the Early Trials (P < 0.02). No significant differences between run trials were found for the rating of perceived exertion, oxygen uptake, heart rate, and change in urine specific gravity. It was concluded that the consumption of fluids earlier in the cycle phase of the Olympic distance triathlon benefits the run and overall performance time.     

Effect of time interval between food intake and exercise on substrate oxidation during exercise in obese and lean children

Background & aims

Exercise induces adaptations in fat metabolism favourable to the treatment of obesity. However, time interval between meal and exercise alters substrate bioavailability and oxidation during exercise. The aim of this study was therefore to investigate the effect of time interval between food intake and exercise on substrate oxidation rates in obese and lean children.

Methods

The metabolic responses to exercise of nine obese children (10.3 ± 1.8 years; %body fat: 36.1 ± 6.1) and seven lean children (9.2 ± 1.6 years; %body fat: 22.2 ± 4.1) were compared 1 h (time interval 1, TI1) and 3 h (TI3) after a standardized breakfast.

Results

Despite significantly lower plasma glucose and insulin concentrations and large effect size suggesting a higher plasma FFA availability (lean, 1.43, obese 0.98), fat oxidation was not significantly increased in TI3 compared to TI1 in both lean and obese children. Fat oxidation contributed marginally to energy expenditure during exercise (<20%) in both conditions and groups but was moderately increased during TI3 compared to TI1 in lean children (effect size: 0.54).

Conclusions

The low contribution of fat oxidation to energy expenditure during exercise in obese and lean children fed 3 h before exercise questions the efficacy of moderate intensity exercise to favourably affect fat balance.     

Changes in beverage intake between 1977 and 2001

OBJECTIVE: To examine American beverage consumption trends and causes. METHODS: Nationally representative data from the 1977-1978 Nationwide Food Consumption Survey, the 1989-1991 and 1994-1996 (also for children aged 2 to 9 years in 1998) Continuing Surveys of Food Intake by Individuals (CSFII), and 1999-2001 National Health and Nutrition Examination Survey were used in this study. The sample consisted of 73,345 individuals, aged >or=2 years. For each survey year, the percentage of total energy intake from meals and snacks was calculated separately for respondents aged 2 to 18 years, 19 to 39, 40 to 59, and >or=60. The percentage of energy intake by location (at home consumption or preparation, vending, store eaten out, restaurant/fast food, and school), as well as for specific beverages was computed separately for all age groups. The proportion consumed, mean portion size, and number of servings were calculated. RESULTS: For all age groups, sweetened beverage consumption increased and milk consumption decreased. Overall, energy intake from sweetened beverages increased 135% and was reduced by 38% from milk, with a 278 total calorie increase. These trends were associated with increased proportions of Americans consuming larger portions, more servings per day of sweetened beverage, and reductions in these same measures for milk. CONCLUSIONS: There is little research that has focused on the beneficial impacts of reduced soft drink and fruit drink intake. This would seem to be one of the simpler ways to reduce obesity in the United States.     

Restricting fluid intake during a single meal did not affect food intake in older adults

Restricting fluid intake has been shown to decrease ad libitum food intake in animals and young adult humans. The purpose of this study was to determine if restricting fluid intake during a meal affects food intake in older adults. In a crossover counterbalanced design, 24 subjects (11 m, 13 f), 61-95 years, received lunch at a congregate meal site. Identical meals were accompanied by a volume of water equal to either 40% (restricted) or 100% (control) of each subject's usual lunch fluid intake. Pre-meal urine osmolality and specific gravity were used as indicators of hydration status. Weighed food intake was not different between the restricted and control conditions (400 g/2875 kJ and 408 g/2971 kJ, respectively). No significant correlations were found between urine osmolality or specific gravity and food intake, either in response to fluid restriction or per kg body weight. These results suggest that the appetite of healthy free-living older adults is not affected by fluid restriction during a single eating episode.     

Development of a brief questionnaire to assess habitual beverage intake (BEVQ-15): sugar-sweetened beverages and total beverage energy intake

IntroductionEnergy-containing beverages, specifically sugar-sweetened beverages, may contribute to weight gain and obesity development. Yet, no rapid assessment tools are available which quantify habitual beverage intake (grams, energy) in adults.ObjectiveDetermine the factorial validity of a newly developed beverage intake questionnaire (BEVQ) and identify potential to reduce items.MethodsParticipants from varying economic and educational backgrounds (n=1,596, age 43±12 years, body mass index [calculated as kg/m²] 31.5±0.2) completed a 19-item BEVQ (BEVQ-19). Beverages that contributed <10% to total beverage, or sugar-sweetened beverages, energy and grams were identified for potential removal. Factor analyses identified beverage categories that could potentially be combined. Regression analyses compared BEVQ-19 outcomes with the reduced version's (BEVQ-15) variables. Inter-item reliability was assessed using Cronbach's α. Following BEVQ-15 development, a subsequent study (n=70, age 37±2 years; body mass index 24.5±0.4) evaluated the relative validity of the BEVQ-15 through comparison of three 24-hour dietary recalls' beverage intake.ResultsThree beverage items were identified for elimination (vegetable juice, meal replacement drinks, and mixed alcoholic drinks); beer and light beer were combined into one category. Regression models using BEVQ-15 variables explained 91% to 99% of variance in the four major outcomes of the BEVQ-19 (all P<0.001). Cronbach's α ranged .97 to .99 for all outcomes. In the follow-up study, BEVQ-15 and three 24-hour dietary recalls' variables were significantly correlated with the exception of whole milk; BEVQ-15 sugar-sweetened beverages (R²=0.69), and total beverage energy (R²=0.59) were more highly correlated with three 24-hour dietary recalls' than previously reported for the BEVQ-19. The BEVQ-15 produced a lower readability score of 4.8, which is appropriate for individuals with a fourth-grade education or greater.ConclusionsThe BEVQ-19 can be reduced to a 15-item questionnaire. This brief dietary assessment tool will enable researchers and practitioners to rapidly (administration time of ～2 minutes) assess habitual beverage intake, and to determine possible associations of beverage consumption with health-related outcomes, such as weight status.     

Dose-dependent effects of beverage protein content upon short-term intake

Protein is considered to be more satiating than carbohydrate, quantified by energy adjustment and subjective appetite. However, the effect of increasing protein content upon short-term energy adjustment in beverage contexts is unclear. This study used a repeated-measures, cross-over design. 28 male volunteers (18–35 years) ate a standard breakfast in the laboratory and 210 min later consumed one of four preloads 30 min prior to an ad libitum pasta meal. Three of the preloads were isocaloric (1155 kJ) mixed composition dairy fruit drinks (300 g) of low (13% protein energy/87% carbohydrate energy), medium (25% protein energy/75% carbohydrate energy) and high (50% protein energy/50% carbohydrate energy) protein content. The control drink was a low energy (328 kJ) alternative. Results indicated a dose response effect of preload protein level on intake (g) at the ad libitum meal. Ad libitum intake was: control (637.6 g ± 39.7), low (596.9 g ± 40.5), medium (546.9 g ± 34.7), and high protein (533.6 g ± 42.3). 100% compensation was not achieved; however total energy intake after the medium and high protein drinks did not differ significantly from control. There were no significant differences in hunger and fullness ratings. Our findings support the view that increasing the protein composition of beverages relative to carbohydrate proportionally affects short-term subsequent intake in controlled conditions.     

Effect of beverage glucose and sodium content on fluid delivery

It has become commonplace for Randomized Controlled Trials (RCTs) to be analyzed according to Intention-to-Treat (ITT) principles in which data from all subjects are used regardless of the subjects' adherence to protocol. While ITT analyses can provide useful information in some cases, they do not answer the question that motivates many RCTs, namely, whether the treatments differ in efficacy. ITT tends to reduce information by combining two questions, whether the intervention is effective and whether, as implemented, it has good compliance. Because these questions may be separate there is a risk of misuse. Two examples are presented that demonstrate this potential for abuse: a study on the effectiveness of vitamin E in reducing cardiovascular risk and comparisons of low fat and low carbohydrate diets. In the first case, a treatment that is demonstrably effective is described as without merit. In the second, ITT describes as the same, two diets that actually have different outcomes. These misuses of ITT are not atypical and are not technical problems in statistics but have real consequences for scientific principles and health recommendations. ITT analyses may answer the question of what happens when treatments are recommended but are inappropriate where separate information on adherence and performance is available. It is proposed that results of RCTs, or any experimental study, be reported, not in terms of the analyses that were performed, but rather in terms of the questions that the analyses can answer properly.