I think people make a lot of fuss about peri-workout nutrition (what you eat immediately before and after a work out). There is obviously an impact but to me the arguments of those who train fasted and then eat after the session make more sense for several reasons (e.g. here)
Anyway here is a study which looks at what you eat after training and its effects:
So low calorie gets the fat mobilised......low carb increases insulin sensitivity.
Any comments, ideas?
Energy deficit after exercise augments lipid mobilization but does not contribute to the exercise-induced increase in insulin sensitivity.
The content of meals consumed after exercise can impact metabolic responses for hours and even days after the exercise session. The purpose of this study was to compare the effect of low dietary carbohydrate (CHO) vs. low energy intake in meals after exercise on insulin sensitivity and lipid metabolism the next day. Nine healthy men participated in 4 randomized trials. During the control trial (CON) subjects remained sedentary. During the other 3 trials, subjects exercised (65%VO2peak; cycle ergometer and treadmill exercise) until they expended ~800 kcal. Dietary intake during CON and one exercise trial (BAL) was designed to provide sufficient energy and carbohydrate to maintain nutrient balance. In contrast, the diets after the other 2 exercise trials were low in either CHO (LOW-CHO) or energy (LOW-EN). The morning after exercise we obtained a muscle biopsy, assessed insulin sensitivity (Si; IVGTT) and measured lipid kinetics (isotope tracers). Although subjects were in energy balance during both LOW-CHO and CON, the lower muscle glycogen concentration during LOW-CHO vs. CON (402+/-29 vs. 540+/-33 mmol/kg dw, P<0.01) coincided with a significant increase in Si (5.2+/-0.7 vs. 3.8+/-0.7 (mU/L)(-1)(.)min(-1); P<0.05). Conversely, despite ingesting several hundred fewer kcals after exercise during LOW-EN compared with BAL, this energy deficit did not affect Si the next day (4.9+/-0.9, and 5.0+/-0.8 (mU/L)(-1)(.)min(-1)). Maintaining an energy deficit after exercise had the most potent effect on lipid metabolism, as measured by a higher plasma triacylglycerol concentration, and increased plasma fatty acid mobilization and oxidation compared with when in nutrient balance. Carbohydrate deficit after exercise, but not energy deficit, contributed to the insulin sensitizing effects of acute aerobic exercise. Whereas maintaining an energy deficit after exercise augmented lipid mobilization. Key words: carbohydrate, glycogen, insulin resistance, triglyceride.
Anyway here is a study which looks at what you eat after training and its effects:
- The study was to compare the effect of low carbohydrate vs. low calorie intake in post exercise meals on insulin sensitivity and lipid metabolism the next day.
- Maintaining an energy deficit after exercise (i.e. low calorie) had the most potent effect on lipid metabolism
- Carbohydrate deficit after exercise, but not energy deficit, contributed to the insulin sensitizing effects of acute aerobic exercise.
- Maintaining an energy deficit after exercise augmented lipid mobilization.
So low calorie gets the fat mobilised......low carb increases insulin sensitivity.
Any comments, ideas?
Energy deficit after exercise augments lipid mobilization but does not contribute to the exercise-induced increase in insulin sensitivity.
The content of meals consumed after exercise can impact metabolic responses for hours and even days after the exercise session. The purpose of this study was to compare the effect of low dietary carbohydrate (CHO) vs. low energy intake in meals after exercise on insulin sensitivity and lipid metabolism the next day. Nine healthy men participated in 4 randomized trials. During the control trial (CON) subjects remained sedentary. During the other 3 trials, subjects exercised (65%VO2peak; cycle ergometer and treadmill exercise) until they expended ~800 kcal. Dietary intake during CON and one exercise trial (BAL) was designed to provide sufficient energy and carbohydrate to maintain nutrient balance. In contrast, the diets after the other 2 exercise trials were low in either CHO (LOW-CHO) or energy (LOW-EN). The morning after exercise we obtained a muscle biopsy, assessed insulin sensitivity (Si; IVGTT) and measured lipid kinetics (isotope tracers). Although subjects were in energy balance during both LOW-CHO and CON, the lower muscle glycogen concentration during LOW-CHO vs. CON (402+/-29 vs. 540+/-33 mmol/kg dw, P<0.01) coincided with a significant increase in Si (5.2+/-0.7 vs. 3.8+/-0.7 (mU/L)(-1)(.)min(-1); P<0.05). Conversely, despite ingesting several hundred fewer kcals after exercise during LOW-EN compared with BAL, this energy deficit did not affect Si the next day (4.9+/-0.9, and 5.0+/-0.8 (mU/L)(-1)(.)min(-1)). Maintaining an energy deficit after exercise had the most potent effect on lipid metabolism, as measured by a higher plasma triacylglycerol concentration, and increased plasma fatty acid mobilization and oxidation compared with when in nutrient balance. Carbohydrate deficit after exercise, but not energy deficit, contributed to the insulin sensitizing effects of acute aerobic exercise. Whereas maintaining an energy deficit after exercise augmented lipid mobilization. Key words: carbohydrate, glycogen, insulin resistance, triglyceride.
Comments
I think one needs to have defined goals when dealing with PWO nutrition---if body comp and weight loss are the goal, a calorie deficit and low cal intake PWO makes sense.
If one if attempting to gain mass, I'm still in favor of enabling insulin to enhance protein synthesis. Lots o' opinions flying around about this, but that's my 2 cents.
Martin at LeanGains has this down to an artform! Can't wait for his book to hit the shelves.
I don't know exactly what they mean in this paper by lipid mobilization, but a shift in use of lipid for fuel would certainly accomplish this too (moving fat out of stores and into muscles for use). In addition, the blood glucose is kept lower since the muscles are actively scavenging the glucose in an attempt to refill glycogen stores. Caloric restriction alone may allow glycogen stores to rapidly refill. So fat may be mobilized, but it won't be used preferentially. I'd say that's not optimal.
Cynthia