Fasting before exercise and the effect on endurance, aerobic, and strength training | Rhonda Patrick
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An abundance of scientific data clearly demonstrates that eating a carbohydrate-rich meal prior to endurance exercise training – more than 60 minutes' duration – markedly improves performance in humans. Eating prior to participating in shorter training periods, however, blunts the beneficial effects associated with training in the fasted state, especially those associated with enhanced mitochondrial fatty acid oxidation. In this clip, Dr. Rhonda Patrick discusses the circumstances under which eating prior to exercise is beneficial versus detrimental.
[Mike]: So this is from Angel or Angel, I hope I got the name right. "So I practice a simple 12-hour eating window and a 24-hour fast once a week." So it was intermittent fasting with a 24-hour fast per week. "My question is, are there any downsides to training fasted, as I usually do? The exercises involved are heavyweight training and moderate cardio afterwards. Just wanted know if I'm metabolically doing harm or having adverse effects of the intended goals. Thanks and love your work. "
[Dr. Patrick]: Great question. There have been meta-analysis of studies done. So that just means there's lots of studies that have looked at, for example, doing physical activity, either aerobic or anaerobic activity, in a fasted state versus pre-exercise feedings. So you eat before exercise. And a meta-analysis has just kind of aggregates all those studies that have been done and looks at what the data says. And so meta-analysis that had been done on that topic have shown that pre-feeding before exercise, it seems to improve long-duration aerobic exercise, so durations longer than 60 minutes, but it doesn't seem to really have much of an effect on performance if it's aerobic exercise less than 60 minutes.
On a similar note, it's also pre-feeding, you know, eating before you exercise has also been shown to improve anaerobic exercise, so like run till exhaustion, but it doesn't really seem to have much of a significant effect on high-intensity interval training. So there is a little bit of a performance enhancement with eating before you work out in terms of long-duration aerobic exercises.
[Mike]: Triathletes, long-distance running, things like that.
[Dr. Patrick]: Right. Which actually makes sense.
[Mike]: But for weight training, it sounds like, if you're keeping it within 60 minutes. ..
[Dr. Patrick]: So even less than, yeah, even running, you know, less than 60 minutes or a high-intensity interval training class. But what's really interesting is those meta-analysis showed that eating before you exercise... So if you're training-fasted, you get really robust enhancements in glucose sensitivity, but really robust enhancements in your mitochondrial adaptations to using fatty acids. So basically, your mitochondria become really primed for fatty acid use, which makes sense. If you're in a fasted state, you know, you're depleting your glucose and you have more of these fatty acids that are available for energy.
There's a lot of increased activity in genes that regulate fatty acid metabolism. That's really expressed when you train in a fasted state. Interestingly, when you feed before you train, those adaptations are blunted with respect to the fatty acid uptake. Yeah, like the really priming your mitochondria to be like robust to use fatty acids as a source of energy. You still get glucose, you know, effects and enhancements and stuff, even when you're training, when you, you know, eat something beforehand. But it seems as though those fatty acid adaptations that the mitochondria shift to are blunted somewhat.
[Mike]: So it sounds like for Angel or Angel that, you know, if you're doing kind of a weightlifting with cardio, it shouldn't be a dramatic effect.
[Dr. Patrick]: I will add to that because I think even one of the previous questions you were asking, someone was asking about the amino acids, wanting amino acid take before they train. And they were wanting to like for hypertrophy, you know, so basically wanting to grow more muscle. I will say that there have been studies looking at, there's been a lot of research that has been done looking at, you know, is there this anabolic window that you have to take in amino acids and protein to like, you know, increase muscle growth.
And I think, over the past few years, studies have, it's been pretty consensus that there's a lot longer time that you have. It used to be thought like this is one-hour window and you have to down this protein shake immediately, or you're going to miss it. I don't think that's the case. I think that there's been a lot of research that's come out, showing that you actually can take in amino acid or protein hours after a workout.
However, if you're going into your workout fasted, let's say you've been fasting for 16 hours, you aren't storing protein. So in that case, if you are doing a fasted strength training workout, you may want to consume protein within an hour after that.
[Mike]: Got it. Good distinction, if you're in a fasted state.
[Dr. Patrick]: Yeah. If you're in a fasted state, like a pretty fasted state.
[Mike]: Yeah. That's a great recap for on Angel or Angel.
Important for the endocrine enhancing properties of exercise. Exerkines are exercise-induced hormonal-like factors which mediate the systemic benefits of exercise through autocrine, paracrine, and/or endocrine properties.[1]
A molecule composed of carboxylic acid with a long hydrocarbon chain that is either saturated or unsaturated. Fatty acids are important components of cell membranes and are key sources of fuel because they yield large quantities of ATP when metabolized. Most cells can use either glucose or fatty acids for this purpose.
A broad term that describes periods of voluntary abstention from food and (non-water) drinks, lasting several hours to days. Depending on the length of the fasting period and a variety of other factors, intermittent fasting may promote certain beneficial metabolic processes, such as the increased production of ketones due to the use of stored fat as an energy source. The phrase “intermittent fasting” may refer to any of the following:
- Time-restricted eating
- Alternate-day fasting
- Periodic fasting (multi-day)
The thousands of biochemical processes that run all of the various cellular processes that produce energy. Since energy generation is so fundamental to all other processes, in some cases the word metabolism may refer more broadly to the sum of all chemical reactions in the cell.
Tiny organelles inside cells that produce energy in the presence of oxygen. Mitochondria are referred to as the "powerhouses of the cell" because of their role in the production of ATP (adenosine triphosphate). Mitochondria are continuously undergoing a process of self-renewal known as mitophagy in order to repair damage that occurs during their energy-generating activities.
The process of generating energy that occurs when mitochondria couple oxygen with electrons that have been derived from different food sources including glucose, fatty acids, and amino acids.
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