Learn four ways to control your blood sugar, get rid of stubborn carbohydrate-related body fat, and reduce your risk of diabetes with exercise.
In last week’s episode, you discovered two potent ways to control your blood sugar, and why you should be controlling your blood sugar in the first place if you’re serious about your health or your waistline! In today’s article, we’re going to delve into two more strategies. Let’s jump right in.
Strategy #3: Post-Prandial Walks
A few years ago, I was inspired to begin setting a rule to move or walk for at least a few minutes after each meal when I read an interesting Japanese study entitled, “Postprandial lipaemia: effects of sitting, standing and walking in healthy normolipidaemic humans.”
This study compared the effects of sitting, standing, and walking on postprandial fat storage in healthy Japanese men. The fifteen participants in the study completed three two-day postprandial trials (you may remember from last week’s article that “post-prandial” means “after a meal”) in a random order: 1) sitting, 2) standing, and 3) walking. On day one of the sitting trial, participants rested. On day one of the standing trial, participants stood for six, 45-min periods. On day one of the walking trial, participants walked briskly for 30 minutes at approximately 60% of maximum heart rate. On day two of each trial, participants rested and consumed test meals for breakfast and lunch. The researchers then collected blood samples in the morning and afternoon on day one, and in the fasted state and at 2, 4 and 6 hours postprandially on day two. On day two, they found serum fat concentrations were 18% lower in the walking trial compared to the sitting and standing trials, proving that postprandial lipaemia was not reduced when standing (or, of course, sitting) after a meal but was reduced after low-volume, easy walking for 30 minutes.
The study “Postprandial Walking is Better for Lowering the Glycemic Effect of Dinner than Pre-Dinner Exercise in Type 2 Diabetic Individuals” takes this science even one step further and looks at the effect of walking before a meal vs. walking after a meal.
In this study, twenty minutes of self-paced, easy walking done shortly after meal consumption resulted in lower blood glucose levels at the end of exercise compared to values at the same time point when subjects had walked pre-dinner. In addition, the investigators in this study found that one hour of aerobic exercise performed in fasted state prior to dinner had a minimal impact on post-dinner glucose levels, but when performed two hours after the meal, induced a significant decrease in plasma glucose levels. So, from what we know thus far, it looks like if you’re going to go on a walk at some point in the evening around dinner, you’re better off doing it after dinner rather than before dinner, and that you get benefits when it’s as short as 20 minutes (although I’d highly suspect you get benefits from any movement at all!).
The same study also makes another interesting observation about the timing of moderate aerobic exercise around a meal and the effect on blood sugar of this exercise: specifically that postprandial, morning moderate intensity exercise decreases blood sugar levels after a morning meal, but this effect does not persist during and after the following lunch meal. This means that if you exercise in the morning, you’re probably going to still want to maintain at least low-level physical activity (e.g., a standing or walking workstation) between breakfast and lunch if you want to continue to reap the benefits of that exercise.
The study also reports that moderate bicycling exercise after any meal (breakfast, lunch, or dinner) results in a significant decrease in blood glucose levels and that both postprandial high-intensity exercise and longer bouts of walking (e.g. two hours versus one hour) reduce blood glucose levels and insulin secretion, suggesting that the effect of exercise is related more to total energy expenditure rather than to peak exercise intensity, leading the researchers to conclude that it is possible that the short duration of the exercise bout in this study (20 minutes) could have had a greater impact blood sugar if either the intensity or its duration had been increased. This is backed up by the study entitled, “Effect of Post-Prandial Exercise Duration on Glucose and Insulin Responses to Feeding,” which found that longer bouts of exercise after a meal produce a greater decrease in glucose and insulin.
Once again, sugar transporters play a big role here, and researchers reported that “the binding of insulin to its cellular receptors in muscle and adipose tissues recruits GLUT4 transport proteins to the cell surface that facilitates glucose transport. Muscular contractions themselves are known to stimulate glucose transport into muscle cells without the need for insulin through an independent mechanism, but in an additive manner, thereby potentiating the effects of post-meal exercise.”
So what do we know so far from all these studies? An excellent strategy to control blood sugar would be to set a habit of exercising before breakfast in a fasted state, using either longer aerobic exercise or brief high intensity exercise, and then, if time permits, to go on an easy 20-60 minute walk after dinner.
OK, there’s one more strategy, so let’s keep on rolling!