How many times do you hear the experts talking about how important it is to eat before a meal to "fuel your workout?" I think I hear this as often as the advice to immediately eat, or scarf down the protein shake, after your workout. If you're like me, it seems like you hear it non-stop.
While I will concede that working out on an empty stomach and delaying a post-workout meal can seem counterintuitive at first blush, and run counter to the conventional wisdom, I don’t think that makes them wrong.
Having a helping of carbs, to supposedly fuel your muscles, and your workout, can be counterproductive if burning fat is among the goals of the workout.
If you want to liberate energy from the body before you go hard, do a warm-up on a stationary bike or a treadmill. It will help begin the process of mobilizing energy for your workout.
There is some conflicting data on whether there is an optimal “post-workout window.” However, to claim that there is no benefit from strength training, if you don't eat within 45 minutes, outside of calories burned (which I actually think should not be part of a rationale for weightlifting) is spurious, at best. Realistically, a single post-workout shake, or meal, will have a minimal impact on the overall nutrition of the individual.
Tipton et al. (2003) looked at the responsiveness of protein synthesis for a day following a workout. They found that the amount of synthesis reflected a 24-hour period. MacDougall et al. (1995) demonstrated a window > 24-hours; Phillips et al. (1997) found there to be a 48-hour window.
It has also been been shown in the literature, that drinks/shakes consumed immediately after a workout resulted in 30% lower protein synthesis rates than consuming the meal an hour after training (Tipton et al., 2001; Rasmussen et al., 2000).
Again, eating also will slow-down the fat-burning phase that typically occurs (or even begins in the case of high intensity training protocols) after the workout.
The hormonal, enzymatic, and cellular responses to exercise don’t require that an organism has a 45-minute timer on protein synthesis following a bout of exertion. Insulin sensitivity, for example, has been shown to remain significantly elevated for up to 10 hours (De Vany, The New Evolution Diet, p. 105), which allows more time for the entry of substrates into the muscle.
In this sense, the only way the muscles are going to starve is from chronic subnutrition and not from acute meal-timing.
If you have adequate stores of glycogen to begin with, you don’t need to supplement your diet with protein and carbs. Although, I will say it’s probably true if you were Lance Armstrong trying to win a mountain stage of 160 km, you would want to make sure that you have topped off glycogen levels, but fat loss is the last thing on his mind, and the relatively constant fueling throughout the workout is to spare the body of using its own energy stores, which actually runs counter to the goals of most people trying to lose body fat.
I would just argue that you should have enough endogenous glycogen to appropriately fuel your workout, and the same philosophy would hold true regarding replenishing your glycogen stores following a workout: you generally have plenty of time to replenish your glycogen stores and the body will do a good job of repleting it on its own if your overall nutrition is sound.
As another aside, but related to the post-workout window, I think eating immediately following a workout will have the tendency to suppress metabolic gene expression when compared to a delay between exercise completion and feeding.
There has also been prior research showing that exercise produces reactive oxygen species (ROS), which makes sense, and it has been recommended to take antioxidants post-workout as a logical assumption.
In a relatively recent study, it was shown that the exogenous antioxidants actually hindered the body’s natural antioxidant defense capabilities.
Ristow et al. (2009) published an article “Antioxidants prevent health-promoting effects of physical exercise in humans” which concluded:
Having a helping of carbs, to supposedly fuel your muscles, and your workout, can be counterproductive if burning fat is among the goals of the workout.
If you want to liberate energy from the body before you go hard, do a warm-up on a stationary bike or a treadmill. It will help begin the process of mobilizing energy for your workout.
There is some conflicting data on whether there is an optimal “post-workout window.” However, to claim that there is no benefit from strength training, if you don't eat within 45 minutes, outside of calories burned (which I actually think should not be part of a rationale for weightlifting) is spurious, at best. Realistically, a single post-workout shake, or meal, will have a minimal impact on the overall nutrition of the individual.
Tipton et al. (2003) looked at the responsiveness of protein synthesis for a day following a workout. They found that the amount of synthesis reflected a 24-hour period. MacDougall et al. (1995) demonstrated a window > 24-hours; Phillips et al. (1997) found there to be a 48-hour window.
It has also been been shown in the literature, that drinks/shakes consumed immediately after a workout resulted in 30% lower protein synthesis rates than consuming the meal an hour after training (Tipton et al., 2001; Rasmussen et al., 2000).
Again, eating also will slow-down the fat-burning phase that typically occurs (or even begins in the case of high intensity training protocols) after the workout.
The hormonal, enzymatic, and cellular responses to exercise don’t require that an organism has a 45-minute timer on protein synthesis following a bout of exertion. Insulin sensitivity, for example, has been shown to remain significantly elevated for up to 10 hours (De Vany, The New Evolution Diet, p. 105), which allows more time for the entry of substrates into the muscle.
In this sense, the only way the muscles are going to starve is from chronic subnutrition and not from acute meal-timing.
If you have adequate stores of glycogen to begin with, you don’t need to supplement your diet with protein and carbs. Although, I will say it’s probably true if you were Lance Armstrong trying to win a mountain stage of 160 km, you would want to make sure that you have topped off glycogen levels, but fat loss is the last thing on his mind, and the relatively constant fueling throughout the workout is to spare the body of using its own energy stores, which actually runs counter to the goals of most people trying to lose body fat.
I would just argue that you should have enough endogenous glycogen to appropriately fuel your workout, and the same philosophy would hold true regarding replenishing your glycogen stores following a workout: you generally have plenty of time to replenish your glycogen stores and the body will do a good job of repleting it on its own if your overall nutrition is sound.
As another aside, but related to the post-workout window, I think eating immediately following a workout will have the tendency to suppress metabolic gene expression when compared to a delay between exercise completion and feeding.
There has also been prior research showing that exercise produces reactive oxygen species (ROS), which makes sense, and it has been recommended to take antioxidants post-workout as a logical assumption.
In a relatively recent study, it was shown that the exogenous antioxidants actually hindered the body’s natural antioxidant defense capabilities.
Ristow et al. (2009) published an article “Antioxidants prevent health-promoting effects of physical exercise in humans” which concluded:
Molecular mediators of endogenous ROS defense (superoxide dismutases 1 and 2; glutathione peroxidase) were also induced by exercise, and this effect too was blocked by antioxidant supplementation. Consistent with the concept of mitohormesis, exercise-induced oxidative stress ameliorates insulin resistance and causes an adaptive response promoting endogenous antioxidant defense capacity. Supplementation with antioxidants may preclude these health-promoting effects of exercise in humans.
I think something similar could be happening when we focus so much on exogenous sources of nutrients to essentially fight our own battles for us; we wind up suppressing self-regulating factors that would otherwise be expressed.
Nassim Taleb said it well in Art De Vany's book The New Evolution Diet, where he stated (and I think wrote this in his notes on his website as well):
There has to be a negative correlation between energy intake and energy expenditure. We work hard in response to hunger; there is no natural, ecological reason to work hard if we are well fed - what's the point? - yet the prevailing wisdom doesn't seem to be aware of this elementary evolutionary logic. A predator mammal does not eat breakfast to hunt; it hunts in response to the need to get breakfast
That said, in the same book, De Vany points out that we are hardwired to be lazy overeaters. He posits that we evolved when "food was scarce and life was full of arduous physical activity" so our bodies tell us to eat as much as we can, whenever we can, and likewise conserve energy whenever possible.
I'm not sure if our ancestors had it so rough, but it makes sense from an evolutionary perspective that there were some hairy times (Ice Ages come to mind) where this would be critical. Similar to animals being able to hibernate in order to survive on no food.
I still think you would have a hard time significantly fattening our lean ancestors by allowing them to eat as much game and vegetables as they desired and let them be as lazy as they wanted. In other words, in the long run, it wouldn’t matter whether you’re fueling up in the morning or evening or even how much you are moving; the quality of the food would ostensibly dictate the quantity you would eat and how much energy you would have to move.
Also, Martin Berkham tries to eat his cake, and have it, too, (literally?) where he recommends consuming branched-chain amino acids (BCAAs) during a fast and before a workout to get the benefits both from fasting and protein consumption, helping to combine the stimulatory effects of protein synthesis of fasted training with a pre-workout protein-induced metabolism boost.
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