Postprandial hyperlipemia produces long-term derangements in lipid/lipoprotein metabolism, vascular endothelial dysfunction, hypercoagulability, and sympathetic hyperactivity which are strongly linked to atherogenesis. The purpose of this review is to (1) provide a qualitative analysis of the available literature examining the dysregulation of postprandial lipid metabolism in the presence of obesity, (2) inspect the role of adiposity distribution and sex on postprandial lipid metabolism, and (3) examine the role of energy deficit (exercise- and/or energy restriction-mediated), isoenergetic low-carbohydrate diets, and omega-3 (n-3) fatty acid supplementation on postprandial lipid metabolism. We conclude from the literature that central adiposity primarily accounts for sex-related differences in postprandial lipemia and that aerobic exercise attenuates this response in obese or lean men and women to a similar extent through potentially unique mechanisms. In contrast, energy restriction produces only mild reductions in postprandial lipemia suggesting that exercise may be superior to energy restriction alone as a strategy for lowering postprandial lipemia. However, isoenergetic very low-carbohydrate diets and n-3 fatty acid supplementation reduce postprandial lipemia indicating that macronutrient manipulations reduce postprandial lipemia in the absence of energy restriction. Therefore, interactions between exercise/energy restriction and alterations in macronutrient content remain top priorities for the field to identify optimal behavioral treatments to reduce postprandial lipemia.
Alex’s Notes: Elevated triglycerides, high LDL and total cholesterol, and low HDL are all indications of poor health that put you and your heart at risk. One of the side-effects of obesity, especially central obesity, is an exacerbated postprandial rise in blood fats. Worse yet, this response is positively correlated with asymptomatic atherosclerosis in persons independent of obesity or diabetes. Nonetheless, fasting triglycerides were a strong predictor of the post-prandial response, and lifestyle seems to be the ultimate variable.
It has been well documented that obese persons have issues clearing fat from their blood, and it is well known that many of the necessary lifestyle interventions that lead to weight-loss also lead to improved health through other biomarkers such as triglycerides, insulin sensitivity, and cholesterol. Exercise is probably the universal prescription for greater health, so let’s start there.
Regular aerobic exercise reduces blood fat. It also reduces the postprandial elevation of blood fat. However, these effects are short-lived. Nonetheless, assuming you eat within six hours after training (which you should), aerobic exercise is able to reduce the postprandial rise from a variety of meal compositions. Moreover, reductions occur if the exercise is performed after eating as well. Importantly, this refers to light to moderate intensity steady state cardio. High-intensity interval training is just as effective despite less time commitment and lower energy expenditure. But we can’t simply run away from health problems. Fortunately, resistance training may be more effective than aerobic exercise at lowering postprandial blood fat. By the way, these effects go beyond burning calories, as demonstrated by a study showing a deficit produced by exercise had a greater effect than an equal deficit produced by dietary restriction.
No matter, diet is another crucial aspect of health and lifestyle interventions. Now, I am no fan of dogmatic low-carbohydrate diets. However, given the propensity of obese and sick individuals to be insulin resistant, some dietary restriction is prudent. It has even been suggested that the improvements in blood fat from exercise are greater when paired with carbohydrate restriction. Additionally, because of the insulin resistance, these improvements from exercise are abolished when a high-carbohydrate meal follows the workout session. And since protein intake usually stays somewhat constant in a typical ad libitum diet, food will be rich in either fat or carbohydrates, and low-fat diets have been shown to reduce HDL cholesterol and increase fasting blood fat levels. We also previously established that omega-3 fatty acids – specifically, EPA & DHA – are protective against heart disease and improve blood lipid profiles.
In short, exercise and diet to improve health. Under the context of this article, both aerobic and resistance training are critical, and reducing carbohydrate intake is beneficial independent of weight loss. Just replace the bread with some fatty fish for the omega-3s.