Mealtime Walking Study to Improve Postprandial Metabolic Response

This randomized crossover trial will investigate the metabolic responses following the consumption of a bagel+juice meal under 3 conditions: control, fiber (positive control), and postmeal walk in15 healthy adults. It is hypothesized that the postmeal walk will reduce glycemia, insulinemia, and oxidative stress similar to fiber.

The study will follow a randomized, crossover design. Participants and the investigator will be blinded for the control treatments but not for the walk treatment. Participants will complete 3 meal tests; tests are separated by about 1 week. An initial screening visit will be scheduled for the online survey respondents that meet the inclusion criteria and are willing to consider participation. At this visit, written consent will be secured followed by further screening for the exclusion criteria and the collection of demographic and health history data and anthropometric measures. A fasting blood sample will be collected for glucose analysis. Participants will be scheduled for experimental testing and provided with instructions and calendars. Participants will be given at least one week's notice if they do not qualify for the trial based on fasting glucose concentrations. On the day prior to each experimental day, the participants will consume 2 bagels (54 g carbohydrate/bagel), and on the night prior to each visit, participants will consume a standard dinner of their choice. (The bagels will be provided to participants and the standardized dinner will be documented. The bagels and standardized dinner meal will facilitate controlled 'glycogen loading' prior to testing.) No other food will be consumed after this dinner meal, and participants will fast overnight until they arrive at the research center the next morning (e.g., no food or beverage with the exception of water). Fasting blood (1 tablespoon) will be collected and the test meal (bagel+juice) will be consumed. Postprandial blood samples will be collected for 4 hours (see below). The subjects will not be allowed to consume any food or beverage (with the exception of water) through the duration the visit. A snack will be provided to participants once the testing is over. Glucose: 0,15,30,60,120, 180, 240 Insulin: 0, 30, 120, 180, 240 Oxidative Stress Markers: 0, 180, 240 The blood insulin level will be determined in venous blood by RIA. Capillary blood glucose will be determined with a glucometer. Oxidative stress, e.g., total antioxidant capacity, IL-6, and TBARS will be assessed using microplate analyses kits.

Test meal [bagel with butter (20 g) and apple juice (240 ml) with added sugar (24 g)] The meal was a total of 640 kcal (100 g carbohydrate, 21 g fat, 10 g protein. Participants remained seated in the laboratory with minimal activity for the four hours following test meal consumption. One week later the test meal was consumed with fiber (36 g, Metamucil powder, Procter&Gamble, Cincinnati, OH) added to the apple juice (active) and participants remained seated in the laboratory with minimal activity for the four hours following test meal consumption . One week later participants were given 5 minutes to transition to the treadmill following consumption of the test meal and began walking on a motorized treadmill at their calculated preferred walking speed for 15 minutes (experimental). Afterwards participants remained seated in the laboratory with minimal activity for the remainder of the four hours following test meal consumption

Test meal [bagel with butter (20 g) and apple juice (240 ml) with added sugar (24 g)] The meal was a total of 640 kcal (100 g carbohydrate, 21 g fat, 10 g protein. 9 grams of soluble viscous fiber from psyllium husk (36 g, Metamucil powder, Procter&Gamble, Cincinnati, OH) was mixed with the apple juice. Participants remained seated in the laboratory with minimal activity for the four hours following test meal consumption. One week later participants were given 5 minutes to transition to the treadmill following consumption of the test meal and began walking on a motorized treadmill at their calculated preferred walking speed for 15 minutes (experimental). Afterwards participants remained seated in the laboratory with minimal activity for the remainder of the four hours following test meal consumption. One week later the test meal was consumed, and participants remained seated in the laboratory with minimal activity for the four hours following test meal consumption (placebo).

Test meal [bagel with butter (20 g) and apple juice (240 ml) with added sugar (24 g)] The meal was a total of 640 kcal (100 g carbohydrate, 21 g fat, 10 g protein. Participants were given 5 minutes to transition to the treadmill following consumption of the test meal and began walking on a motorized treadmill at their calculated preferred walking speed for 15 minutes. Afterwards participants remained seated in the laboratory with minimal activity for the remainder of the four hours following test meal consumption One week later the test meal was consumed, and participants remained seated in the laboratory with minimal activity for the four hours following test meal consumption (placebo comparator). One week later the test meal was consumed with fiber (36 g, Metamucil powder, Procter&Gamble, Cincinnati, OH) added to the apple juice and participants remained seated in the laboratory with minimal activity for the four hours following test meal consumption (active comparator).

Inclusion Criteria: obese (BMI ≥ 30 kg/m2) nonsmoking sedentary fasting capillary blood glucose that measured from 5.6 to 6.9 mmol/L Exclusion Criteria: answered "yes" to any of the questions on the "Par-Q & You" questionnaire refused to discontinue antioxidant supplement use for several weeks prior to and during the study prescribed medication use (unless use was consistent for the 3 months prior to the study and intake remained consistent throughout the study duration) food allergies or medical conditions that impacted normal functioning of the gastrointestinal tract