The influence of walking performed immediately before meals with moderate fat content on postprandial lipemia

Acute effects of daily step count on postprandial metabolism and resting fat oxidation: a randomized controlled trial

To examine the effects of daily step count on same-day fat oxidation and postprandial metabolic responses to an evening high-fat mixed meal (HFMM). Ten healthy participants (5 females, 30 ± 7 yr) completed four different daily step counts-2,000 (2 K), 5,000 (5 K), 10,000 (10 K), and 15,000 (15 K) steps-on separate days in randomized order. On experimental days, participants ate the same meals and walked all steps on an indoor track at a pace of 100 steps/min in three roughly equal bouts throughout the day. After the final walking bout, participants' resting energy expenditure (REE), respiratory exchange ratio (RER), and fat oxidation rate (FATOX) were measured. Blood samples were obtained before (BL) and 30-, 60-, 90-, 120-, and 240-min following consumption of an HFMM (960 kcal; 48% fat) to measure triglycerides (i.e., postprandial lipemia; PPL), nonesterified fatty acids (NEFAs), insulin, and glucose. Two-way ANOVAs indicated condition effects where PPL was significantly higher after 2 K versus 10 K (+23 ± 8 mg/dL, P = 0.027), and NEFAs were significantly higher after 15 K versus 2 K (+86 ± 23 µmol/L; P = 0.006). No differences were found for insulin, glucose, or REE among conditions (all P > 0.124). Similarly, RER (P = 0.054; ηp2 = 0.24) and FATOX (P = 0.071; ηp2 = 0.23) were not significantly different among conditions. In young adults, 10 K steps elicited the greatest decrease in PPL, an established cardiovascular disease risk factor. NEFA levels were highest after the 15 K condition, likely due to alterations in adipose tissue lipolysis or lipoprotein lipase activity with increased activity.NEW & NOTEWORTHY This randomized controlled trial demonstrated that walking 10,000, compared with 2,000, steps/day significantly reduced postprandial lipemia (PPL), an independent predictor of cardiovascular disease (CVD) following same-day evening meal consumption. These experimental data support walking 10,000 steps/day to lower CVD risk.

Effect of Prior Exercise on Postprandial Lipemia: An Updated Meta-Analysis and Systematic Review

The purpose of this systematic review was to synthesize the results from current literature examining the effects of prior exercise on the postprandial triglyceride (TG) response to evaluate current literature and provide future direction. A quantitative review was performed using meta-analytic methods to quantify individual effect sizes. A moderator analysis was performed to investigate potential variables that could influence the effect of prior exercise on postprandial TG response. Two hundred and seventy-nine effects were retrieved from 165 studies for the total TG response and 142 effects from 87 studies for the incremental area under the curve TG response. There was a moderate effect of exercise on the total TG response (Cohen's d = -0.47; p < .0001). Moderator analysis revealed exercise energy expenditure significantly moderated the effect of prior exercise on the total TG response (p < .0001). Exercise modality (e.g., cardiovascular, resistance, combination of both cardiovascular and resistance, or standing), cardiovascular exercise type (e.g., continuous, interval, concurrent, or combined), and timing of exercise prior to meal administration significantly affected the total TG response (p < .001). Additionally, exercise had a moderate effect on the incremental area under the curve TG response (Cohen's d = -0.40; p < .0001). The current analysis reveals a more homogeneous data set than previously reported. The attenuation of postprandial TG appears largely dependent on exercise energy expenditure (∼2 MJ) and the timing of exercise. The effect of prior exercise on the postprandial TG response appears to be transient; therefore, exercise should be frequent to elicit an adaptation.

Effects of exercise before and/or after a mixed lunch on postprandial metabolic responses in healthy male individuals

PURPOSE

Exercise plays an important role in preventing and treating postprandial dysmetabolism. We investigated the postprandial metabolic responses to a standard lunch when a session of aerobic exercise is performed in the early postprandial phase or divided between the pre- and postprandial period.

METHODS

Nine healthy volunteers consumed a standardised mixed lunch and rested for the following 3 h (Con) or performed 40 min of cycling at 65% V̇O₂max after lunch (CPPEx), or two 20-min sessions, one before (SplitEx1) and the other after lunch (SplitEx2), at the same intensity.

RESULTS

At 1-h post-lunch, a significant reduction (P < 0.001) in glycaemia was observed for CPPEx (- 25 ± 10%) and SplitEx (- 34 ± 7%) compared to Con. Yet, a post-exercise rebound lessened the exercise effect on the glycaemic area under the curve (AUC) at 2 and 3 h. At 1 h, a significant reduction (P < 0.009) in plasma insulin (SplitEx - 53 ± 31%; CCPEx - 48 ± 20%) and C-peptide (SplitEx - 57 ± 20%; CCPEx - 47 ± 24%) was observed compared to Con. Glucose-dependent insulinotropic polypeptide (GIP) increased after the meal, without differences between conditions. Compared with SplitEx1, cortisol response was attenuated during SplitEx2 and CPPEx. At 3 hours, triglyceride AUC was significantly higher (P = 0.039) in SplitEx compared to Con (+ 19 ± 8%).

CONCLUSION

Forty minutes of postprandial exercise or 20 min of pre- and postprandial exercise are both effective at attenuating the glycaemic and insulinaemic response to a mixed lunch, while a higher lipaemia was found in the pre- and postprandrial exercise condition.

Increased Meal Frequency With Exercise Mitigates Postprandial Triacylglycerol

PURPOSE

This study examined how manipulating meal frequency, with and without exercise, affects postprandial triacylglycerol (TAG).

METHODS

Fourteen sedentary men completed four 2-day trials in a noncounterbalanced random cross-over order: (1) consumption of 1 large high-fat milkshake without exercise (1-CON), (2) consumption of 2 smaller high-fat milkshakes without exercise (2-CON), (3) consumption of 1 large high-fat milkshake with exercise (1-EX), and (4) consumption of 2 small high-fat milkshakes with exercise (2-EX)-total energy intake was standardized across trials. On day 1, participants rested (1-CON and 2-CON) or walked briskly for 60 minutes (1-EX and 2-EX). On day 2, participants consumed either a single large high-fat milkshake (75% fat; 1-CON and 1-EX) for breakfast or 2 smaller isoenergetic milkshakes (2-CON and 2-EX) for breakfast and lunch. Plasma TAG were measured fasting and for 7 hours after breakfast.

RESULTS

Peak incremental TAG was 30% lower on 2-EX than 1-CON (P = .04, d = 0.38). Postprandial TAG increased more rapidly in the first 4 hours in 1-CON than other trials; but at 6 hours, TAG was exaggerated in 2-CON compared with 1-CON.

CONCLUSIONS

Increasing meal frequency after exercise, without altering overall fat intake, attenuates postprandial TAG.

The Timing of Activity after Eating Affects the Glycaemic Response of Healthy Adults: A Randomised Controlled Trial

There is scant information on how a time lag between the cessation of eating and commencement of physical activity affects postprandial glycaemia. Starting at baseline (t = 0), participants ingested white bread containing 50 g of available carbohydrates within 10 min. Using two crossover conditions, we tested the effect over 2 h on postprandial glycaemia of participants undertaking light activity at 15 or 45 min following baseline and compared it with a sedentary control condition. The activity involved cycling on a stationary ergometer for 10 min at 40 revolutions per min with zero resistance. Seventy-eight healthy adults were randomized to the 15 or 45 min activity arm and then randomised to the order in which they undertook the active and sedentary conditions. Cycling 45 min after baseline changed the course of the blood glucose response (likelihood ratio chi square = 31.47, p < 0.01) and reduced mean blood glucose by 0.44 mmol/L (95% confidence interval 0.14 to 0.74) at 60 min when compared with the sedentary control. No differences in postprandial blood glucose response were observed when cycling started 15 min after baseline compared with the sedentary control. Undertaking activity after waiting for 30 min following eating might be optimal in modifying the glycaemic response.

The repeatability of the abbreviated (4-h) Oral Fat Tolerance Test and influence of prior acute aerobic exercise

PURPOSE

The Oral Fat Tolerance Test (OFTT) is regarded as a repeatable measure used to assess postprandial triglyceride (TAG) levels, with higher levels observed in cardio-metabolic disorders. Acute aerobic exercise intervention before OFTT reduces the TAG response, but the repeatability of this effect is unknown. The aim of this study was to determine the repeatability of the abbreviated 4-h OFTT with and without immediate prior aerobic exercise.

METHODS

On four separate days, healthy adult male participants underwent two 4-h OFTT (n = 10) and another two 4-h OFTT with 1-h of standardised moderate intensity aerobic exercise performed immediately before meal ingestion (n = 11). The OFTT meal composition included 75.4 g total fat, 21.7 g carbohydrate and 13.7 g protein. Venous blood was sampled at baseline and hourly up to 4 h after the OFTT meal ingestion, and TAG area under the curve (AUC) was calculated.

RESULTS

Nonparametric Bland-Altman analysis of 4-h TAG AUC revealed that 9 of 10 repeat measurements fell within ±15 % of the median TAG AUC for the OFTT. By contrast, two of 11 repeat measurements fell within ±15 % of the median TAG AUC for the OFTT undertaken with 1-h prior aerobic exercise.

CONCLUSIONS

The 4-h OFTT is a repeatable test of postprandial TAG responses in healthy men. However, aerobic exercise performed immediately before OFTT considerably increases the variability of TAG AUC. These findings have implications for interpretation of research studies investigating exercise intervention performed immediately before OFTT. Future studies should also investigate the repeatability of exercise performed 8-24 h before OFTT.

Postprandial lipemia: factoring in lipemic response for ranking foods for their healthiness

One of the limitations for ranking foods and meals for healthiness on the basis of the glycaemic index (GI) is that the GI is subject to manipulation by addition of fat. Postprandial lipemia, defined as a rise in circulating triglyceride containing lipoproteins following consumption of a meal, has been recognised as a risk factor for the development of cardiovascular disease and other chronic diseases. Many non-modifiable factors (pathological conditions, genetic background, age, sex and menopausal status) and life-style factors (physical activity, smoking, alcohol and medication use, dietary choices) may modulate postprandial lipemia. The structure and the composition of a food or a meal consumed also plays an important role in the rate of postprandial appearance and clearance of triglycerides in the blood. However, a major difficulty in grading foods, meals and diets according to their potential to elevate postprandial triglyceride levels has been the lack of a standardised marker that takes into consideration both the general characteristics of the food and the food’s fat composition and quantity. The release rate of lipids from the food matrix during digestion also has an important role in determining the postprandial lipemic effects of a food product. This article reviews the factors that have been shown to influence postprandial lipemia with a view to develop a novel index for ranking foods according to their healthiness. This index should take into consideration not only the glycaemic but also lipemic responses.

Realistic Test-Meal Protocols Lead to Blunted Postprandial Lipemia but Similar Inflammatory Responses Compared with a Standard High-Fat Meal

Background: A substantial increase in triglycerides (TGs) after a meal is associated with an increased risk of cardiovascular disease. Most studies investigating the effects of a meal on TGs have not used meals that reflect typical consumption. Objective: The objective of this study was to compare the TG and inflammatory responses of true-to-life meals, containing moderate fat and energy contents, with a high-fat, high-energy, low-carbohydrate meal (HFM) typically used to test TG responses. Methods: Nine healthy, insufficiently active men [mean ± SD age: 25.1 ± 6.7 y; body mass index (in kg/m2): 25.8 ± 7.0; <150 min moderate- to vigorous-intensity physical activity/wk] completed 3 meal trials in random order: an HFM (17 kcal/kg, 60% fat), a moderate-fat meal (MFM; 8.5 kcal/kg, 30% fat), and a biphasic meal (BPM), in which participants consumed the full MFM at baseline and 3 h postmeal. Blood samples were collected via an indwelling catheter at baseline and hourly for 6 h. Results: Peak blood TGs were significantly greater (P = 0.003) after the HFM (285.2 ± 169.7 mg/dL) than after the MFM (156.0 ± 98.7 mg/dL), but the BPM (198.3 ± 182.8 mg/dL) was not significantly different from the HFM (P = 0.06) or the MFM (P = 0.99). Total area under the curve for TGs was greater after the HFM (1348.8 ± 783.7 mg/dL × 6 h) than after the MFM (765.8 ± 486.8 mg/dL × 6 h; P = 0.0005) and the BPM (951.8 ± 787.7 mg/dL × 6 h; P = 0.03), although the MFM and BPM were not significantly different (P = 0.72). There was a significant time-by-meal interaction for interferon γ, but not for interleukins 6, 8, or 10. Conclusion: These findings in insufficiently active, healthy young men suggest that the large TG response after HFMs in previous studies may not reflect the metabolic state of many individuals in daily life.

90 Minutes of Moderate-Intensity Exercise does not Attenuate Postprandial Triglycerides in Older Adults

To determine whether 90 minutes of moderate-intensity exercise, prior to a high fat meal, attenuates postprandial triglycerides (PPT) in older adults. Eight sedentary older adult volunteers (mean ± SD age = 58 ± 8 years, BMI 26.5 ± 4.2); completed two trials consisting of exercise and a no-exercise control. Exercise trials involved 90 minutes of moderate-intensity exercise 60% heart rate reserve (HRR). Following exercise, an overnight fast of 12-16 hours was performed. Participants were given a high fat meal that consisted of 146 grams of CHO, and 92 grams of fat and instructed to rest. Lipid levels were collected at pre-feeding, 1, 2, 3, and 4 hours post feeding. The control trial involved no exercise, performed an overnight fast of 12-16 hours, and was given the high fat meal followed by four hours of rest and data collection. There was no difference in PPT between the control and exercise trials (p < 0.05). Triglycerides (TG) increased in both trials over pre-feeding values (pre-feeding 123.13 ± 65.03 con. 111 ± 53.9 ex., 1hr 161.50 ± 83.77 con. 149 ± 71.03 ex., 2hrs 208.25 ± 120.69 con. 177 ± 97.29 ex., 3hrs 228 ± 146.99 con. 147.25 ± 87.64 ex., 4hrs 211.75 ± 140.15 con. 169.5 ± 68.14 ex). No difference in triglycerides over time was observed among older adults between the exercise and control trials.

Effects of thirty and sixty minutes of moderate-intensity aerobic exercise on postprandial lipemia and inflammation in overweight men: a randomized cross-over study

BACKGROUND

The transient rise in blood lipids following a high-fat meal (HFM), known as postprandial lipemia, is linked to systemic inflammation and cardiovascular disease, but can be blunted by exercise. However, minimal research has investigated the effects of realistic exercise bouts on postprandial lipemia and inflammation in at-risk individuals. The purpose of this study was to assess the effects of moderate-intensity aerobic exercise lasting 30 or 60 min performed the evening before a HFM, on postprandial lipemia and inflammation in overweight, insufficiently active men.

METHODS

In this randomized-crossover study, twelve participants remained sedentary (CON), or performed a brisk walk on a treadmill at 60 % VO2peak for either 30 min (EX-30) or 60 min (EX-60), after which they consumed a small snack (270 kcal) to partially replace exercise energy expenditure. Following a 12-h overnight fast, participants consumed a standard HFM (1 g fat/kg; 1 g CHO/kg; 1117.8 ± 117.0 kcal). Blood draws were performed at baseline (pre-HFM) and 1, 2, 4, 6, and 8 h post-HFM to assess glucose, insulin, lipids, and systemic inflammation.

RESULTS

There were no significant differences (p > 0.05) in fasting triglycerides between EX-60 (118.7 ± 68.3 mg/dL), CON (134.8 ± 66.2 mg/dL) or EX-30 (135.5 ± 85.4 mg/dL). There were no differences in peak, time-to-peak, total or incremental area-under-the-curve between trials for triglyceride response (p > 0.05). There was no significant main effect of time (p > 0.05) in IL-1ra, IL-4, IL-5, IL-6, IL-10 or TNF-α from baseline to 8 h post-HFM in any trial.

CONCLUSIONS

In summary, we found that in overweight, insufficiently active men, neither 30 nor 60 min of moderate-intensity exercise performed 12 h prior to a HFM attenuated postprandial lipemia or inflammation, which could potentially be explained by the partial caloric replacement of exercise energy expenditure.

Effect of prior exercise on postprandial lipemia: an updated quantitative review

Reducing postprandial triglycerides (TG) can lower the risk for cardiovascular disease. The purpose of this study was to perform a meta-analytic review of the literature to estimate the effect of prior exercise on postprandial lipemia. A total of 121 effects were found from 76 studies for the total TG response and 70 effects from 44 studies for the incremental area under the curve (iAUC) TG response. The weighted mean effect was moderate for the total TG response, Cohen's d = −0.60 ( P < 0.0001), and for the iAUC response, Cohen's d = −0.59 ( P < 0.0001). Moderator analysis revealed women exhibited a larger reduction ( P < .01) in the total TG response following exercise ( d = −0.96) than men ( d = −0.57); high-intensity interval training induced a larger reduction ( P < .05) in the iAUC response ( d = −1.49) than aerobic ( d = −0.58) or resistance ( d = −0.13) exercise, and participants maintaining an energy deficit following exercise exhibited a greater reduction in the iAUC response ( d = −0.67) compared with participants in energy balance ( d = −0.28). We conclude that prior acute exercise reduces postprandial lipemia, with the magnitude of effect influenced by sex, type of exercise, and energy deficit following exercise.

The latest on the effect of prior exercise on postprandial lipaemia

This review examines the effect of prior exercise on postprandial triacylglycerol (pTAG) concentrations, an independent risk factor for cardiovascular diseases. Numerous studies have shown that a single bout of exercise reduces pTAG concentrations; however, several modulators such as exercise energy expenditure/deficit, mode of exercise (aerobic/resistance/high intensity/intermittent exercise or combinations), type of meal (moderate or high fat), time frame between exercise and meal and target group may individually or in conjunction influence this effect. On the other hand, at least for aerobic exercise, training reduces pTAG concentrations transiently (~2 days); therefore, exercise sessions should be frequent enough to maintain this clinically significant improvement. For the healthy population, it seems that a subject's preference and ability determine which type of exercise to undertake to attenuate pTAG concentrations; an energy expenditure of ~30 kJ/kg of body mass (or ~2-2.5 MJ) not combined with a corresponding increase in energy intake is required; for resistance or intermittent exercise, for those following a moderate rather than a high-fat diet, and for those with obesity (expressed as kJ/kg of body mass), a smaller energy expenditure is probably sufficient. More studies are needed to investigate dose-response/plateau effects, as well as the threshold of energy expenditure in those with diabetes mellitus and other high-risk populations. Finally, investigation of the underlying mechanisms may be clinically helpful in individualizing the appropriate intervention.

Getting the label in: practical research strategies for tracing dietary fat

The observation that events occurring after consumption of a meal can directly affect metabolic risk has been gaining interest over the past 40 years. As a result, the desire for investigators to conduct postprandial studies has also increased. Study design decisions pertaining to the choice of meal quantity and composition are more difficult than may be readily apparent, and there is now ample evidence available in the literature to suggest that what is fed on the test day significantly affects postprandial metabolism and can therefore influence interpretation of results. In addition, events occurring before the testing day (food intake and activities) can also have an impact on the observed postprandial response. The goal of this review is to present aspects of study design critical to the investigation of postprandial metabolism. These details include subject preparation, meal quantity, form and composition, as well as sampling protocols for measuring metabolites. Key factors and practical examples are provided to minimize the impact of nonresearch variables on subject variability. Finally, aspects related to using stable isotope tracers to measure metabolism of meal fat are discussed, including choice of tracer form, dose and delivery in food. Given that fed-state events contribute significantly to chronic disease risk, improved methods to study the absorption and disposal of food energy will support the development of strategies designed to prevent and treat diseases associated with overconsumption of nutrients.

Exercising for metabolic control: is timing important?

Atherosclerosis-related cardiovascular disease and diabetes mellitus are leading causes of mortality in the world and both disorders are closely related to the postprandial phenomena. Regular exercise is being strongly advocated as a precious tool in easing the global burden of chronic disease. Although exercise intensity, duration and frequency are well established in current guidelines for healthy and diabetic individuals, there is still no consensus on the optimal timing of exercise in relation to the last meal. The present paper reviews the existing literature on the 'when?' of aerobic exercise for metabolic control in healthy and diabetic individuals. Effective control of postprandial phenomena might prove to be a useful tool in the prevention of chronic disease. Exercise appears to influence glycemic and triglyceridemic responses differently depending on the meal composition and time lapse from meals. In healthy individuals, fasted-state exercise favors postprandial triglyceridemic control and the insulin sensitivity related to it. However, there is a lack of data on this matter in diabetic patients. On the other hand, when postprandial glycemia is of concern, aerobic exercise works better when performed after a meal, both in healthy and in diabetic patients.

Exercise prior to a freely requested meal modifies pre and postprandial glucose profile, substrate oxidation and sympathovagal balance

Background

The effects of exercise on glucose and metabolic events preceding and following a freely initiated meal have never been assessed. Moreover, the relationship between these events and sympathovagal balance is not known. The objective of this study was to determine whether exercise prior to a freely requested meal modifies the pre- and postprandial glucose profile, substrate oxidation and sympathovagal balance.

Methods

Nine young active male subjects consumed a standard breakfast (2298 ± 357 kJ). After 120 min, they either performed 75 min of exercise on a cycle ergometer (EX - 70% VO_2max) or rested (RT). Lunch was freely requested but eaten ad libitum only during the 1^st session, and then energy intake was fixed across conditions. Glucose and sympathovagal balance were assessed continuously using a subcutaneous glucose monitoring system and analysis of heart rate variability, respectively. Every 5 min, a mean value was calculated for both glucose and sympathovagal balance. Substrate oxidation was determined by calculating the gas exchange ratio when lunch was requested and 180 min after the onset of eating.

Results

Preprandial glucose profiles were found in 72% of the sessions and with a similar frequency under both conditions. Meals were requested after a similar delay (40 ± 12 and 54 ± 10 min in EX and RT respectively; ns). At meal request, sympathovagal balance was not different between conditions but CHO oxidation was lower and fat oxidation higher in EX than in RT (-46% and +63%, respectively; both p < 0.05). Glucose responses to the meal were higher in incremental (+ 48%) but not in absolute value in EX than in RT, with a higher fat oxidation (+ 46%, p < 0.05), and a greater vagal withdrawal (+ 15%, p < 0.05).

Conclusions

These results show that exercise does not impair preprandial glucose declines at the following meal freely requested, but leads to an increased postprandial glucose response and an elevated fat oxidation, an effect that vagal withdrawal may contribute to explain.

Substrate Utilization is Influenced by Acute Dietary Carbohydrate Intake in Active, Healthy Females

The present study compared the metabolic responses between a single low-carbohydrate (LC) and low-fat (LF) meal followed by an aerobic exercise bout in females. Subjects included 8 active, premenopausal females. Subjects completed a LC and LF testing session. Respiratory gas exchange (RER) measurements were taken for 20 min fasted, for 55 min postprandial (PP), and during 30 min of exercise. Blood was collected for assessment of glucose (G), insulin (IN), triglycerides (TG), and free fatty acids (FFA) during the final 10 min of each time period. The LF meal provided 396 kcal (78% carbohydrate, 7% fat, and 15% protein). The LC meal provided 392 kcal (15% carbohydrate, 68% fat, and 18% protein). No significant differences existed between test meals for fasting blood measurements. PP IN (μU·mL(-1)) levels were significantly lower following LC compared to LF [10.7 (6.1) vs. 26.0 (21.0)]. Postexercise (PE) FFA (mEq·L(-1)) levels were significantly greater following LC [1.1 (0.3) vs. 0.5 (0.3)]. PE TG (mg·dL(-1)) levels were significantly greater following LC [152.0 (53.1) vs. 114.4 (40.9)]. RER was significantly lower at all time points following LC compared to LF. In moderately active adult females, ingestion of a single LC meal resulted in greater lipid oxidation at rest and during exercise as compared to a single LF meal. Although macronutrient distribution appears to have dictated substrate utilization in the present study, more research is needed regarding the long-term effects of macronutrient redistribution with and without exercise on substrate utilization. Key pointsThe relative carbohydrate content of a single meal has a significant impact on postprandial metabolism and substrate utilization in healthy, active females.A single bout of aerobic exercise performed within an hour of meal ingestion has the potential to modify the postprandial response.Interventions aimed at improving body composition and preventing chronic disease should focus on dietary macronutrient redistribution and postprandial metabolism in concert with exercise training.

Is the effect of prior exercise on postprandial lipaemia the same for a moderate-fat meal as it is for a high-fat meal?

Moderate-intensity exercise can lower the TAG response to a high-fat meal; however, the British diet is moderate in fat, and no study to date has compared the effect of such exercise on responses to high-fat and moderate-fat meals. The present work investigated the effect of brisk walking performed 13 h before intake of both high-fat and moderate-fat meals on postprandial plasma TAG concentrations. Eight inactive, overweight men completed four separate 2 d trials, i.e. rest (Con) or a 90-min treadmill walk (Ex) on the evening of day 1, followed by the ingestion of a moderate-fat (Mod) or high-fat (High) meal on the morning of day 2. High-fat meals contained 66 % of total energy as fat, while the percentage was 35 % for moderate-fat meals; both the meals were, however, isoenergetic. On day 2, venous blood was sampled in the fasted state, 30 and 60 min after ingesting the test meal and then hourly until 6 h post-meal. Exercise reduced plasma TAG concentrations significantly (P < 0·001), with no exercise × meal interaction (P = 0·459). Walking reduced the total TAG response to a high-fat meal by 29 % (relative to High Con); the same bout of exercise performed before ingesting a moderate-fat meal lowered total TAG by 26 % (compared with Mod Con). The ability of a single moderate-intensity aerobic exercise bout to lower postprandial TAG concentrations is just as great, in percentage terms, when the test meal ingested is of a moderate rather than a high fat content.

Moderate exercise reduces serum triacylglycerol concentrations but does not affect pre-heparin lipoprotein lipase concentrations after a moderate-fat meal in young men

Aerobic exercise has been shown to lower postprandial TAG concentrations after a meal(s) of high-fat content. This study examined the effects of moderate-intensity cycling on postprandial TAG concentrations and pre-heparin lipoprotein lipase concentrations after subjects consumed a meal of moderate-fat content (45 % of total energy). Twelve male subjects, aged 24 (sem 1) years, completed two 2 d trials (exercise and control) at least 1 week apart in a randomised, repeated measures design. On day 1, subjects either cycled for 30 min at 65 % of maximum heart rate in the afternoon or rested (no exercise). On day 2 of both trials, after an overnight stay with an 11 h fast, subjects consumed a test meal of moderate-fat content (0.61 g fat, 1.34 g carbohydrate, 0.37 g protein and 51 kJ energy/kg body mass) for breakfast. Blood samples were collected at baseline (before the exercise or at an equivalent time-point during the control trial on day 1), in the fasted state (0 h) and at 2, 4 and 6 h postprandially on day 2. The total and incremental areas under the serum TAG concentration v. time curve were 30 % (P = 0.039) and 33 % (P = 0.012) lower on the exercise trial compared with the control trial, respectively. Serum pre-heparin lipoprotein lipase concentrations did not differ between the exercise and control trials. These findings demonstrate that 30 min of moderate-intensity cycling performed the day before a meal of moderate-fat content is effective at lowering postprandial serum TAG concentrations but does not affect serum pre-heparin lipoprotein lipase concentrations in young men.

Regulation of postprandial lipemia: an update on current trends

People spend a large percentage of their waking hours in the postprandial state. Postprandial lipemia is associated with disruptions in lipoprotein metabolism and inflammatory factors, cardiovascular disease, MetS, and diabetes. Commonly, the dietary sources of fat exceed the actual needs and the tissues are faced with the excess, with accumulation of chylomicrons and remnant particles. This review will summarize recent findings in postprandial lipemia research with a focus on human studies. The effects of dietary factors and other meal components on postprandial lipemia leads to the following question: do we need a standardized oral lipid tolerance test (OLTT)? An overview of recent findings on FABP2, MTP, LPL, apoAV, and ASP and the effects of body habitus (sex influence and body size), as well as exercise and weight loss, on postprandial lipemia will be summarized.

Prescribing Aerobic Exercise for the Regulation of Postprandial Lipid Metabolism

Prolonged presence of elevated plasma triglycerides (TGs) during the postprandial period has been suggested to increase the risk for coronary artery disease. Aerobic exercise attenuates postprandial lipaemia and this has generally been described as a short-term effect of the exercise. Effects of exercise on postprandial lipaemia have mostly been investigated, and documented, with large exercise-induced energy expenditures (i.e. 1000 kcal). The exact mechanisms involved in the attenuation of postprandial lipaemia with exercise are not completely understood, but it appears that at least two mechanisms are involved: a decrease in TG secretion by the liver and an increase in plasma TG clearance by the muscle. Changes in the metabolism of other lipids, such as those in high-density lipoprotein cholesterol, have been documented only when the exercise is performed some hours before the fat meal. Although factors such as the physical fitness and percentage body fat of an individual are likely to also be involved, the most important factors determining the magnitude of the attenuation in postprandial lipaemia appear to be the magnitude of the exercise-induced energy expenditure and the intensity of exercise. To date, the evidence suggests that healthy individuals can generally induce favourable changes in postprandial lipaemia with aerobic exercise that: (i) is completed during the period extending from 16 hours before a meal through 1.5 hours after a meal; (ii) is of moderate intensity; and (iii) results in an energy expenditure of approximately 500 kcal (or more).