#33 - Fat metabolism, insulin resistance and exercise with Dr Graham Holloway

Dr Glenn McConell chats with Professor Graham Holloway from the University of Guelph in Canada. He is an expert on mitochondrial bioenergetics. We discussed the effect of exercise intensity and duration and exercise training on fat/lipid and carbohydrate metabolism, whether alterations in substrate availability such as high fat diets, high fat meals, high carbohydrate meals etc affect fat oxidation and mitochondrial function and the effect of high fat diets on insulin sensitivity. Central role of ADP.

0:00. Introduction and Graham’s sporting and research journey
6:06. Fat availability and fat oxidation at rest snd during exercise
8:40. Carbohydrate metabolism out-competes fat metabolism
11:25. More energy per unit of oxygen from carbohydrate than fat
13:13. Increased ability to oxidize fat with endurance training
15:21. ADP and breakdown of muscle glycogen
16:20. Less increase in ADP during exercise after ex training
17:45. Effect of exercise intensity and duration on exercise metabolism
23:46. Fat more efficient store of energy
25:32. Does lactate inhibit fat oxidation?
28:47. Exercise training and sparing muscle glycogen during ex
29:40. Maximum fat oxidation rate
31:40. Best intensity of exercise training for mitochondrial adaptations
35:09. High fat diets and fat oxidation during exercise
37:40. Randle cycle/Glucose-fatty cycle
38:28. Meal composition affects what is used for energy
40:06. Excess body lipids/fat contribute to insulin resistance
45:35. Reactive oxygen species, fat and exercise
49:03. Best way to remove excess lipids/fat is to exercise
50:14. Dealing with extra carbohydrate
51:25. One high fat meal can cause insulin resistance
51:54. Insulin resistance and fat oxidation/ADP:
53:15. People with T2D have normal fat oxidation and normal glucose uptake during exercise
55:12. Does insulin resistance cause mitochondrial dysfunction?
58:14. Does mitochondrial dysfunction cause insulin resistance?
59:19. One high fat meal can cause insulin resistance
1:00:43. Ex training protects against fat induced insulin resistance
1:03:12. Acute exercise is protective w/o changing weight
1:04:30. Same mechanisms in adipose tissue/heart as skeletal muscle
1:06:04. Acute vs chronic reactive oxygen species/stress/exercise
1:10:10. Controversy around mitochondrial dysfunction/insulin resistance
1:11:42. Increasing fat oxidation by high fat diets
1:14:17. Takeaway messages
1:16:00. Outro (9 secs)

Inside Exercise brings to you the who's who of research in exercise metabolism, exercise physiology and exercise’s effects on health. With scientific rigor, these researchers discuss popular exercise topics while providing practical strategies for all.

The interviewer, Emeritus Professor Glenn McConell, has an international research profile following 30 years of Exercise Metabolism research experience while at The University of Melbourne, Ball State University, Monash University, the University of Copenhagen and Victoria University.

He has published over 120 peer reviewed journal articles and recently edited an Exercise Metabolism eBook written by world experts on 17 different topics (https://link.springer.com/book/10.1007/978-3-030-94305-9).

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