For Nutrition Experts, How does Exercise Impact Carb Utilization?

[Fearless_Bum]

Just out of curiosity. 

I've been eating refined carbs like white rice for example, I don't eat candy or any sugar for that matter, but I'll eat potatoes and white rice and I haven't had much of an issue. 

I'm suspecting exercise may have improved how my body uses carbs and that's why refined carbs don't affect me as much as they used to. 

I do cardio in the mornings and weights in the evenings on weekdays (sometimes I'll do just cardio/weightlifting instead of 2-a-days)

For the health experts, any ideas on this?

Edited November 12, 2021 by Fearless_Bum

[Michael569]

13 hours ago, Fearless_Bum said:

I'm suspecting exercise may have improved how my body uses carbs and that's why refined carbs don't affect me as much as they used to. 

I'm not exactly clear on the mechanism but I recall it may have something to do with the Glucose Transporter 4 (GLUT4) a door-key if you like, that opens the cellular "gates" for glucose entry. In Insulin Resistance this molecule often does not work properly (IR is more complex than that) and so the cellular "doors" for glucose remain shut despite docking of insulin. 

And I believe what happens is that skeletal muscle stimulation (exercise) kinda uses a secondary mechanism of some sort that forces GLUT 4 to move and open up the glucose entry gate and allows more glucose in. In healthy individual this may mean that even more glucose can be absorbed in cells and faster. 

There is also the fact that exercise seems to improve insulin sensitivity peripherally, 

"In healthy man a single bout of exercise has been shown to increase insulin stimulated whole body glucose uptake, as measured by glucose clamp, for at least 16 hours post-exercise [11,89]. In addition, acute exercise has been shown to decrease the insulin response to an oral glucose tolerance test (OGTT) [129], suggesting that peripheral insulin sensitivity is increased"

https://www.researchgate.net/publication/12632588_Exercise_and_Insulin_Sensitivity_A_Review - this is an interesting review if you wanna geek-out on some of those details. This is from 2000 so much more detail might be known if you looked at more recent papers but they describe the potential mechanism nicely including a nice graphics. 

[RobertZ]

Sorry I can't answer this question directly (Im not an expert) except that exercise tends to improve insulin sensitivity in some cases. 

However, from what I unserstand, exercise can process carbs in different ways, depending on various factors, including insulin sensitivity, rate of metabolism, and the extent to which a diet includes both high fat and high carbs. 

For example, take a person who has been bulking on high fat and high carbs for a while. If this person tries to introduce more white rice, the body may shuttle the additional carbs into fat cells, despite vigorous exercise. If this person was not exercising, then exercise could likely improve insulin sensitivity; but even if the person was exercising hard, they may still encounter insulin insensitivity, and adding more carbs will just tend toward fat despite exercise.

The same person who spends a bit of time clearing out their muscle glycogen and liver carb stores (eg fasting for a couple days, cutting back on callories for a little while) and thereby increase insulin sensitivity, might then gradually introduce increasing amounts of white rice (and other foods, of course)--to the same level of calories as before, or even surpass their previous caloric intake, and the exercise will then drive relatively more of these carbs into muscle over the long term.

Many people esteem high protein and high fat diets for great reasons. However, there is another interesting diet based on high complex carbs (think oatmeal 5x a day, sweet potatoes, and so on), moderate protein and very minimal fat. This diet does not require a long period to take effect. As long as a person avoids high fructose sugars, this diet can ramp up the metabolism. You eat protein first, and then eat carbs until full--any bit of hunger, eat again. Eat whenever hungry--even have a meal one hour after another meal, if feeling any hunger. With exercise, this diet ramps up metabolism so that a person can lose more fat on 3200 calories than they would normally lose on 1200 or 1400 calories. Some people report losing fat rapidly on 4500 calories per day by ramping up their metabolic rate.

Edited November 13, 2021 by RobertZ

[Fearless_Bum]

@RobertZ @Michael569 thanks for the contributions guys! 

I'm pretty lax with how I eat as I'm in good shape and I don't like candy/sugar based products anyways. 

I am going to wean off into complex carb dominant diet though.