Effect of meal manipulation and exercise on postprandial lipaemia

Project Number
RI 11/12 SB

Project Duration
May 2013 - December 2016

Status
In-Progress (Extended)

Abstract
Postprandial lipaemia refers to fat (triglyceride, TG) in the blood after eating and high concentrations are associated with cardiovascular disease. Exercise can reduce postprandial lipaemia and the present proposal aims to conduct two studies to determine how meal frequency with/without exercise and energy replacement after exercise affects postprandial lipaemia. Study 1 Specific Aim: To examine the effect of manipulating meal frequency, in the presence and absence of exercise, on postprandial TG concentrations in Singaporeans. Hypothesis: Two small meals in combination with exercise will result in lower TG responses over 7 hours than a single isoenergetic large meal in the absence of exercise. Study 2 Specific Aim: To examine the effect of using different substrates to replace an exercise-induced energy deficit on postprandial lipaemia. Hypothesis: Replacement of an exercise-induced energy deficit with fat will result in a greater postprandial lipaemia than replacement with glucose. Fifteen Singaporean males, aged 18-35 years, will be recruited to each study. In study 1, volunteers will complete four laboratory trials in random order. They will consume a single large fat test meal or two small fat test meals 3 hours apart the morning after a rest day or having walked for 60 minutes. The two small test meals will be isoenergetic to the large test meal. On all trials, blood samples will be taken fasted and for 7 hours after the start of the first meal to determine TG concentrations and differences compared among trials. In study 2, participants will consume fat test meals, in a random order, the morning after: i) a rest day; ii) a bout of exercise expending 400 kcal at a low exercise intensity; iii) a bout of exercise expending 400 kcal at a low exercise intensity where the energy was replaced with an oral fat load afterward; iv) a bout of exercise expending 400 kcal at a low exercise intensity where the energy was replaced with an oral glucose load afterward. On all trials, blood samples will be taken fasted and for 5 hours after the test meal to determine TG concentrations and differences compared among trials. The Principal Investigator has an established history of studying fat metabolism and the proposed experiments will continue this theme. Study 1 is significant to public health providers in giving dietary advice to the population. Study 2 is novel in examining whether resultant improvements in postprandial lipaemia after exercise are merely a facet of energy deficit or whether substrate use in exercise is important. nergy was replaced with an oral glucose load afterward. On all trials, blood samples will be taken fasted and for 5 hours after the test meal to determine TG concentrations and differences compared among trials. The Principal Investigator has an established history of studying fat metabolism and the proposed experiments will continue this theme. Study 1 is significant to public health providers in giving dietary advice to the population. Study 2 is novel in examining whether resultant improvements in postprandial lipaemia after exercise are merely a facet of energy deficit or whether substrate use in exercise is important.

Funding Source
NIE

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