Time-restricted eating, a form of fasting that limits the period during which a person eats to a 12- to 16-hour window, capitalizes on the benefits associated with both fasting and optimization of the body's circadian biology. The eating window begins when the person consumes their first bite or drink of caloric food or drink. Although some evidence suggests that consumption of black coffee might be permissible (and even beneficial) during fasting, consumption of amino acids will likely negate any of the beneficial effects associated with the practice. In this clip, Dr. Rhonda Patrick discusses the pros and cons of consuming black coffee and amino acids during fasting.
[Mike]: The first question from John Phillips is, "Can you discuss in further detail why you recommend a water-only fast versus consuming coffee or amino acids while in a fasted state? I'm looking to optimize my morning workouts with amino acids or a caffeine boost, and want to know what benefits I am potentially missing out on versus the benefits I likely still receive." So coffee, amino acids.
[Dr. Patrick]: Yeah. There's a lot in that question there.
[Mike]: Yeah, it's dense.
[Dr. Patrick]: But the coffee question, as you mentioned, is something that is certainly, it's asked quite frequently. And to sort of address that question, I think people mostly are asking it in the context of a type of fasting called time-restricted eating. Time-restricted eating, it has a fasting component to it, but it also has a circadian biology component to it.
And people might go, "Well, what is circadian biology?" And really, you know, just sort of think about the fact that, you know, you're awake during certain times. So you're awake in the morning, you know, early in the morning, your body produces a stress hormone called cortisol, wakes you up, you're alert, you're active, you do all your activities. And then as the day progresses and nighttime comes on, you get sleepy, your body's making melatonin. It helps you with, you know, getting tired and then you go to sleep and things sort of shut down, right? So there's this...
[Mike]: All these natural pathways.
[Dr. Patrick]: Right. It's just sort of this rhythm, this circadian rhythm. That's why they call it, you know, circadian rhythm. So it turns out, you know, every cell in our body has one of those and including, you know, pathways like metabolism. So it's really important to make sure that you're consuming food when, you know, the metabolic pathways are active. You know, you don't want to eat when they're not active. And so a lot of this work has been done by Dr. Satchin Panda at the Salk Institute and some of his colleagues.
You know, they've shown that what activates metabolism is, you know, basically when you take in your first food, you activate those metabolic pathways and then there'll be active for a certain amount of time. And then, as the day goes on, they become less active. For example, if you look at men who eat the same meal early in the morning, and then they eat the same meal later in the evening, same calories, same macronutrient content, everything. They're more insulin sensitive in the morning and they're less insulin sensitive in the evening.
Fatty acid metabolism is the same way. So you may think, well, maybe I'll just eat some fat in the evening. Well, it turns out your fatty acids and being able to use those as well as energy is also on a circadian clock. And it's less active in the evening as well.
So with that said, where does coffee come into play? You know, coffee, if you're just, if you're talking about coffee with cream, you know, obviously, cream got calories and fat and that's, you know, something that would be considered, you know, food, right, cream. If you're talking about just black coffee, coffee without, you know, any...
[Mike]: Or espresso. Like a shot of espresso.
[Dr. Patrick]: Exactly or espresso, something without any calories, essentially. Then the question becomes, does that count as, you know, starting your clocks. And, you know, there's no real direct data that has addressed that question. A couple of my thoughts are for one, we do know that caffeine itself changes the circadian clocks. So if you, you know, give someone a cup of coffee later in the day, it actually shifts the body's circadian clock, that natural rhythm, by like 40 minutes. So coffee itself is changing the circadian clocks.
[Mike]: It's extending it essentially in the evening.
[Dr. Patrick]: Yeah, exactly. And additionally, you know, caffeine is metabolized by the gut. It's also metabolized by the liver. So the question is, does that, you know, activating those metabolic pathways, does that start your clocks? We don't really know if it's enough to, or not. What we do know is that, you know, there have been some studies.
For example, a study done by Dr. Ruth Patterson at UCSD. She looked at time-restricted eating in women that had previously had breast cancer. Women that ate all of their food within 11 hours and they fasted for 13 hours. During that 13 hours, they were allowed to consume caffeine. So black coffee or tea without cream. And even though they consumed the coffee during their fasting period, they still had a 36% reduction in breast cancer recurrence. So they had positive benefits.
Along the same lines, there's been some pilot studies in people with Type 2 diabetes where they've done a time-restricted eating for anywhere between a six to eight-hour window. So they're eating within a shorter window when they're fasting for 16 or more hours a day. They're also allowed to consume caffeine or tea, and they had positive effects on blood glucose regulation, insulin sensitivity, weight loss, you know. So clearly, there's evidence in the scientific literature that if you consume black coffee within that fasting window, there's still positive effects happening.
[Mike]: So if I can paraphrase. While coffee or caffeine may slightly interrupt the circadian window, the metabolic benefits from black coffee or tea without additives are maintained, is that...?
[Dr. Patrick]: It seems as though, you know, at least according to these studies that, you know, it's not negating those metabolic benefits. However, the question becomes, if you were not to consume that, would you have a more robust effect?
[Mike]: Got it.
[Dr. Patrick]: We don't know.
[Mike]: We need to study on this because this is like one of the most common questions we get. But I guess, the early directional research is and for a lot of people, coffee, including myself, coffee is crucial. Okay, for right now, and we'll learn more about the detail level of what's happening maybe.
[Dr. Patrick]: Well, and I also think that if you're talking about just, you know, like I mentioned, time-restricted eating, this is something that you're practicing on a daily basis, right? This is, you're eating your food within an 8- to 12-hour time window, and you're fasting for 16 or, and/or up to, you know, 12 to 16 hours, right? There's other types of fasting, which we can talk about, you know, where you're doing longer.
[Mike]: We're going to get into that in another question with different modalities of fasting.
[Dr. Patrick]: Yeah. And in that case, research has also shown, if you consume black coffee or tea without any calories that there's still benefits.
[Mike]: Great. And what about the amino acid aspect?
[Dr. Patrick]: Right. That's a great question as well. And this sort of touches on another, you know, aspect of the fasting literature. And that is, you know, there are many benefits that occur during a fast, and there are many types of fasting. And when you're actually fasting, some of the things that are occurring are you're deactivating pathways that are typically like a grow pathway, for example, and it's called IGF-1. It's grow, grow pathway. mTOR is another grow, grow pathway. Both of those pathways are activated by amino acids.
And so if you're limiting your amino acid intake along with your calorific intake and everything else, you're going to deactivate those pathways and the deactivation of those pathways...
[Mike]: IGF-1 will go down.
[Dr. Patrick]: IGF-1 will go down, mTOR will go down, and those are essential for the activation of some of the benefits of fasting, including a process called autophagy, which is basically when your cells start to recycle. And interestingly, they seem to recycle damaged components of themselves. So like mitochondria, which are, you know, they're the powerhouse of energy in yourself. Damaged mitochondria can be cleared away.
[Mike]: So spring cleaning is the process of autophagy within your body.
[Dr. Patrick]: Right. You know, pieces of protein, dead cell, things are just in there, it gets rid of them. But mTOR has to be deactivated, IGF-1 has to be deactivated for that to happen. You know, so, and then there's other things as well, like which we can talk about when we get into more of a prolonged type of fast, those things also need to be deactivated. So amino acids would be something that would sort of negate that.
[Mike]: Interrupt that natural reduction of IGF-1, which may interfere with some autophagy.
[Dr. Patrick]: Right.
An intracellular degradation system involved in the disassembly and recycling of unnecessary or dysfunctional cellular components. Autophagy participates in cell death, a process known as autophagic dell death. Prolonged fasting is a robust initiator of autophagy and may help protect against cancer and even aging by reducing the burden of abnormal cells.
The relationship between autophagy and cancer is complex, however. Autophagy may prevent the survival of pre-malignant cells, but can also be hijacked as a malignant adaptation by cancer, providing a useful means to scavenge resources needed for further growth.
A gene encoding a transcription factor (CLOCK) that affects both the persistence and period of circadian rhythms. CLOCK functions as an essential activator of downstream elements in the pathway critical to the generation of circadian rhythms. In humans, polymorphisms in the CLOCK gene have been associated with increased insomnia, weight loss difficulty, and recurrence of major depressive episodes in patients with bipolar disorder.
A steroid hormone that participates in the body’s stress response. Cortisol is a glucocorticoid hormone produced in humans by the adrenal gland. It is released in response to stress and low blood glucose. Chronic elevated cortisol is associated with accelerated aging. It may damage the hippocampus and impair hippocampus-dependent learning and memory in humans.
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 peptide hormone secreted by the beta cells of the pancreatic islets cells. Insulin maintains normal blood glucose levels by facilitating the uptake of glucose into cells; regulating carbohydrate, lipid, and protein metabolism; and promoting cell division and growth. Insulin resistance, a characteristic of type 2 diabetes, is a condition in which normal insulin levels do not produce a biological response, which can lead to high blood glucose levels.
An enzyme that participates in genetic pathways that sense amino acid concentrations and regulate cell growth, cell proliferation, cell motility, cell survival, protein synthesis, autophagy, and transcription. mTOR integrates other pathways including insulin, growth factors (such as IGF-1), and amino acids. It plays key roles in mammalian metabolism and physiology, with important roles in the function of tissues including liver, muscle, white and brown adipose tissue, and the brain. It is dysregulated in many human diseases, such as diabetes, obesity, depression, and certain cancers. mTOR has two subunits, mTORC1 and mTORC2. Also referred to as “mammalian” target of rapamycin.
Rapamycin, the drug for which this pathway is named (and the anti-aging properties of which are the subject of many studies), was discovered in the 1970s and is used as an immunosuppressant in organ donor recipients.
A hormone that regulates the sleep-wake cycle in mammals. Melatonin is produced in the pineal gland of the brain and is involved in the expression of more than 500 genes. The greatest influence on melatonin secretion is light: Generally, melatonin levels are low during the day and high during the night. Interestingly, melatonin levels are elevated in blind people, potentially contributing to their decreased cancer risk.
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.
A chemical reaction in which an atom, molecule, or ion gains one or more electrons.
A metabolic disorder characterized by high blood sugar and insulin resistance. Type 2 diabetes is a progressive condition and is typically associated with overweight and low physical activity. Common symptoms include increased thirst, frequent urination, unexplained weight loss, increased hunger, fatigue, and impaired healing. Long-term complications from poorly controlled type 2 diabetes include heart disease, stroke, diabetic retinopathy (and subsequent blindness), kidney failure, and diminished peripheral blood flow which may lead to amputations.
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