Tag Archive for: fasting

The Bottom Line on Fasting

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In the past four Memos, I’ve focused on explaining fasting. The questions I left you with on Saturday were: “Is it worth it to fast? Is it effective? Is there science to support it?” The answer to all three is yes. I think it can be summed up in one quote from the reference.

“In response to starvation, mammalian cells enter either a non-dividing or a low-dividing state and invest energy resources in cellular protection against various insults.”

While the statement is complicated, it means that metabolism is decreased. That allows the body to shift energy sources from glucose to fat metabolites such as ketones. The body focuses on reducing the production of proteins that can be destructive, such as inflammatory hormones, thereby protecting cells. It also helps improve the immune system so it functions better. The stress of reducing food intake in a controlled fashion helps cells function better.

The research review is available for free; it goes into more detail but demonstrates that fasting is beneficial when used properly. The bulk of the research is on the two- to-five-day fast with fewer than 1,000 calories on the fast day; I’ll use a two-day version before my knee replacement next week to help my body prepare. Just be sure to check with your physician before you fast if you have any metabolic issues such as diabetes or if you take medications, both of which can be impacted by restricting food.

Wednesday is the final scheduled Insider call of 2021. This may be the time to join to help you achieve your health goals in 2022. Hope to see you (or hear you) at 9 p.m. Eastern Time.

What are you prepared to do today?

        Dr. Chet

Reference:Trends Endocrinol Metab. 2018 April; 29(4): 271–280.

Fasting: Two Approaches

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It’s time to get into some real fasting. While there’s nothing wrong with the abstinence approach, abstinence is not really fasting. I’m going to cover two different approaches. The first is known by the moniker 5:2. That means you eat reasonably five days out of the week and you fast two days per week. The second is a straight fasting approach of limiting calories per day that has been used in conjunction with cancer treatment. There’s no specified times to eat in either case, and you can drink any calorie-free beverages of your choosing.

The 5:2 Fast

The 5:2 fasting diet was originally developed about 10 years ago by a British physician/journalist. It’s become commercialized over the years with new additions and materials but essentially, this is how it works:

  • For five days a week, you eat your normal diet. The goal is to eat healthier, but there are no restrictions on the number of calories that you can eat.
  • For two nonconsecutive days of the week, you reduce your caloric intake to 750 calories per day, spread out over the day as you want. Again, the goal is to eat healthy food—and wouldn’t you know it, healthy food is generally low in calories! Your intake should include plenty of vegetables.

That’s it. It’s a way you can eat for the rest of your life if you want to. If you add some exercise and choose a better diet, you could lose weight and get some of the benefits I talked about in earlier Memos.

The Two- to Five-Day Fast

This approach is closer to a true fast than anything else because there are no gimmicks. The goal is to help the immune system and other organs by focusing less on growth and more on repair. This approach was developed by Dr. Valter Longo and has the most research behind it.

The goal is to eat healthy. A vegetarian approach with very low protein can make it very beneficial. Because this is a very low calorie fast, you have to check with your physician before you do it. Here we go:

  • Day 1
    Eat up to 1,200 calories, primarily from vegetables with some protein. Soups and broths make this approach easier. If you wanted to use shakes or smoothies, that’s acceptable as long as you stay under the 1,200 calories for the day.
  • Day 2 through Day 5
    On these days, your calories are restricted: 300 to 500 calories per day. The calories should come primarily from vegetables and again soups and broths are desirable.

When I use this approach, I generally do two days: one 1,200 calorie day and one 500 calorie day, and then eat normally the other five days. You have to be mentally ready if you’re going to do additional days. Eat when you want, whether a single meal or spread throughout the day. The choice is yours.

The Bottom Line

The last four Memos have talked about fasting and abstinence in relation to food intake. The question is why do this at all? Is there science to support it? Is it worth doing? That’s for next week.

What are you prepared to do today?

        Dr. Chet

Fasting: Abstinence Models

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How did you do on your 18:6 abstinence from food if you tried it? The ratio of abstinence to eating can vary. I asked you to try an 18:6 approach. Personally, I did fine—that’s just about my normal eating pattern anyway. I’m going to give you one version of an abstinence model today. I’ll give you two versions of a fasting model on Saturday.

The objective was to avoid food for 18 consecutive hours. The clock begins after your last meal the evening before. If you like to eat late or go out with the gang, that means that you might finish eating at 10 p.m. You wouldn’t eat again until at least two o’clock the following afternoon. Then you would have six hours to eat, ending at 8 p.m., and then the cycle begins again. Just to be clear: you don’t start the clock on the six hours for eating until you actually take your first bite of food. That’s why your last meal might have been 10 p.m. on one day because you didn’t start eating until 4 p.m., because let’s face it things don’t always go to plan.

The question: what do you eat during those six hours? Everybody seems to have an opinion. You could use a ketogenic or Paleolithic approach or you could eat a Mediterranean diet. You could also stuff yourself with all kinds of junk food. Regardless of which approach you decide to use, the goal is to eat better for maximum benefit. You can drink any calorie-free beverages of your choosing.

I’ll give you two different approaches for a fasting plan on Saturday. Until then, if you haven’t tried it, see how you do, with the same proviso for people with serious medical disorders.

What are you prepared to do today?

        Dr. Chet

Fasting vs. Abstinence

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Before I talk about the differences between fasting and abstinence, I want to make it clear that I’m in favor of both approaches when used wisely. I don’t think either is the way you should eat for the rest of your life, but if you have specific objectives to control your weight or to reduce your risk of degenerative disease such as cardiovascular disease, type 2 diabetes, and even reduce your risk of cancer, I think they both can be beneficial. Let’s look at the pluses and minuses of each.

Definitions

Fasting is a controlled reduction in the number of calories eaten in 24 hours.

Abstinence is the complete avoidance of food within a given time frame, whether that’s complete days or specific hours of the day.

Pluses and Minuses: Fasting Versus Abstinence

The pluses:

Both fasting and abstinence take in fewer calories than the body needs, which can help with weight loss if sustained long enough.

Fasting can help you handle hunger because you’re eating something eventually.

Fasting can also force your body to deplete all glycogen stores, depending on the source of the calories.

Abstinence forces the body to use all storage forms of sugars; then it uses stored fat as a fuel, increasing the supply of ketones for fuel.

When fasting, calories can be manipulated during the day to ensure you can eat before exercise if it’s required.

With abstinence, no thinking is necessary; you don’t eat anything when you’re abstaining from food.

The minuses:

With abstinence, you’re taking in no calories, so hunger can become an issue.

If you need to eat before you exercise, abstinence will limit the time of day you can exercise.

When fasting, deciding what to eat and when to eat it requires planning; that can be challenging for some people while making life easier for others.

There are more pluses and minuses for each approach, but I think that these are the most significant upsides and potential downsides of each.

The Bottom Line

As I said at the beginning, I’m in favor of both approaches. They both have merits and challenges—the key is using them wisely.

Next week, I’m going to give you examples of abstinence and fasting and how to use them. In the meantime, give the abstinence approach a ride around the block. Don’t eat for 18 consecutive hours on Sunday or Monday (that includes the time you’re asleep, limiting your eating to just six hours; you get to decide whether to eat the first six or last six consecutive hours you’re awake.) You also get to decide what you’re going to eat. Don’t try it if you have a severe metabolic disorder such as type 1 or uncontrolled type 2 diabetes.

What are you prepared to do today?

        Dr. Chet

The Fasting Dilemma

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I hope you all had a wonderful Thanksgiving. Because we’ve entered the “weight-gain portal” time of the year, let’s talk about the fasting craze that some people are doing and the rest are thinking about trying. As I see it, the problem is the lack of clarity in terminology and subsequently the execution of a fasting program. Terms such as “5:2” and “16:8” are thrown around. What exactly is a fast? What can it do for a person? What’s the best way to do a fast?

The problem begins with defining the term “fast”; there’s no consistent way the term is used, and that includes in the methodology of research studies. Fasting can mean avoiding all food and in some cases drink. That definition can describe fasts done for religious purposes as well as the fasts talked about for weight loss and controlling metabolism.

Another definition of fasting is severely reducing calories; if you lower your intake from 2,000 to 1,400 calories to lose weight, that’s a fast. If you’re drastically reducing calories for two to four days to help reset your immune system, that’s also a fast. But if you’re not consuming any calories, whether for a specific number of hours per day or a whole day, that’s more accurately called “abstinence from food.” Is that a big deal? Yes, and I’ll explain why on Saturday.

What are you prepared to do today?

        Dr. Chet

Building a Healthy Microbiome

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After last week’s Memos on the importance of a healthy microbiome and immune health, let’s review how to have a healthy microbiome to protect your brain and boost your immune system.

First, eat a mostly plant-based diet: some raw, some cooked, some fermented. The raw will give you probiotics and fiber. The cooked, especially whole grains and beans, will give you fiber. The fermented such as sauerkraut and yogurt will give you even more probiotics.

Second, fast once in a while. I covered this in Memos from June, so you can re-read the Memos on fasting and microbiome health.

Third, reduce your refined carbohydrate and sugar intake. Simply put, they provide the bad microbes with the food they need to overtake the good bacteria. Good bacteria need fiber from foods or supplements, so make sure you’re getting 25–30 grams per day.

My knee replacement surgery is scheduled in six days, so I’ve been working on preparing my body to defend against staph infections. I’ll talk about that in Saturday’s Memo.

What are you prepared to do today?

        Dr. Chet

Fasting: Another Piece of the Puzzle

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Fasting is gaining popularity. Actually, periods of complete abstinence from food within a 24-hour cycle is what really seems to be gaining in popularity, but this study doesn’t address intermittent fasting. It examines fasting for a specific period of time before a dietary change—in this case, to the DASH diet. We don’t know if the results would be the same if someone were switching to a ketogenic diet or a paleolithic diet. These are the major results of the study we began examining on Tuesday.

The Results

  • The five-day fast prior to beginning the DASH diet appeared to have positive effects on blood pressure. There was an average drop of eight points in systolic BP and a reduction in the use of medication to lower blood pressure.
  • Subjects adhering to the DASH diet lost weight as well. However, it was not the reduction in weight loss that caused the drop in systolic blood pressure based on their analysis.
  • The immunome, a portion of the total proteome I talked about a few weeks ago, improved. While the exact mechanism is not known, the positive changes in immune proteins appeared to have a positive effect on lowering blood pressure.
  • Researchers also discovered genetic differences between those who responded to the fast and the subsequent DASH diet by lowering their blood pressure and those who did not. The key seems to be in the bacteria that produce short-chain fatty acids. Fasting was identified as a way to increase the bacteria producing those SCFAs.

What Does It Mean?

What are we to conclude? With only 71 total subjects, there’s not a lot of data to generalize to entire populations, but here’s what I think is important.

First, fasting does have a role to play in the health of our microbiome; it also has role to play in our immune function. It’s not completely clear why these changes can occur, but research shows that they do. It may be that eliminating food for a period of time helps the naturally occurring bacteria to function better.

Second, it doesn’t seem to have anything to do with intermittent fasting. It very well may be that complete abstinence from food could get you similar benefits if you were to withhold food for 18 or 20 hours a day and only eat in a very small block of time. But until fasting for a specific amount of days is compared with hourly intermittent fasting, we just don’t have the best answers yet.

The Bottom Line

Fasting, however you define it, appears to have some beneficial effects. If you find a way that fits into your lifestyle, there doesn’t seem to be any reason that you shouldn’t do it unless you have a metabolic disorder and must eat. For example, if you have problems with your blood sugar or take meds that must be accompanied by food, fasting may not be for you.

Here’s my plan: now and then, I’m going to try a reduction to 500 to 800 hundred calories per day for one to three days. That seems to be supported by the most science. It also appears to benefit immune function the most.

Anticipating questions from those doing a ketogenic or paleolithic diet, is the diet after the fast important? Maybe if you select the right foods, such as going vegan during those fasting days, you may get the positive changes in your microbiome. What would happen if you then went on a ketogenic or paleo diet after that? We just don’t know whether the changes would last. This study provided a few pieces of the puzzle, but there’s much we still need to know.

What are you prepared to do today?

        Dr. Chet

Reference: Nat Comm (2021)12:1970. https://doi.org/10.1038/s41467-021-22097-0

Summer Body Prep Time

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This week culminates with the first outdoor holiday of the summer season, and for many of us, the first family cook-out in over a year. Next week I’m going to review a study on the benefits of intermittent fasting, but I want to challenge you to mimic part of the study before the weekend to see how you do. Here’s the task.

For any two consecutive days, cap your eating at 1,200 calories. If you can get by on 1,000 calories, great, but no more than 1,200 and no fewer than 800. The second part is to make them vegan days as well. Don’t think only salads and carrot sticks: beans, legumes, nuts, root vegetables, and every other vegetable and fruit you can think of as well as whole grains. Two days—that’s all. Then you can resume your normal eating if you want. That will give you at least part of experience of the subjects in the intermittent fasting study I’ll review.

The irises in the photo are from our yard. Two years ago, we dug up entire iris beds and replanted them until we ran out of space. This year, they produced more flowers than ever, and they’re just beginning; the ones pictured are hand-me-down yellow ones we got from Paula’s dad and another called “Red at Night.” There are more colors to come, including an electric blue called “Blue Suede Shoes.”

All those flowers don’t happen by accident; neither does a healthier and fitter body. It takes work and it may take a while to see the benefits, just like the irises. Take the vegan-fast challenge and see how you do. Just remember: no lower than 800 calories and no more than 1,200. It will give you a sense of how the subjects initially felt in the study on fasting, the microbiome, and blood pressure.

Paula and I are going to spend this week putting flowers in containers, so this is the only Memo this week. Enjoy the outdoors and if you’re traveling, be safe. See you next week.

What are you prepared to do today?

        Dr. Chet

Can Fasting Reduce Inflammation?

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In this Memo, I’ll review the third paper from the recent journal Cell on fasting and summarize what this all may mean for the use of intermittent fasting.

Researchers used both mice and humans as subjects in a series of studies. The objective was to examine how the immune system responded to a fasting protocol. For the study in humans, the subjects fasted for 19 hours after eating, with blood samples taken before and after the fast. In the mice, a variety of protocols were used. The most common was mice were fed for a short time before food was withheld for the remainder of 24 hours.

In mice and humans, circulating monocytes were reduced. This was important because they were pro-inflammatory in nature; thus inflammation decreased in response to the fasting protocol. In some of the studies, this reduction was maintained even with exposure to pathogens. That means the immune response was not compromised even in animals with induced autoimmune diseases.

Fasting Protocols

Three different studies used at least three different approaches to fasting. In the first study, food was withheld completely for 36 hours. In some phases of the second study, calories were reduced by 50% although the vitamins, minerals, and protein were maintained at normal levels. The final study used a fasting protocol we’re most familiar with: eat within a few hours and liquids only the remainder of the day.

The results were similar in sustaining and perhaps improving the immune system of the animals when placed under pathogenic stress. The only issue is what form of dietary restriction worked best? You can’t ask mice how they felt; you can only check immune system markers. In one of the approaches, the skin of the mice was injured at different times of continued fasting. The healing ability continued until the fast went beyond 48 hours; after that wound-healing was impaired.

The Bottom Line

These studies haven’t changed my approach to fasting. If you’re going to fast to rejuvenate your immune system, don’t play games. Reduce caloric intake to 500 to 800 calories per day for two to three days; those studies show the best benefit. Be sure to select small quantities of the healthiest foods.

Fasting is not abstinence. The current approaches to intermittent fasting are really intermittent abstinence. The idea is to abstain from food completely for 12 to 18 hours while still drinking liquids. That may not be possible for everyone. Some medications have to be taken in relation to food intake. Pre-diabetics and type 2 diabetics should still monitor blood sugar, especially if exercising during the fasting times. The current intermittent fasting approach is more about controlling when you eat than anything else, and that’s something you should do anyway.

I believe in fasting. That’s why I wrote Real-Life Detox—so you could do it right and gain the most benefit. The critical thing is to find a way to eat that you can sustain for the rest of your life, and that includes occasional fasts.

Eat less. Eat better. Move more. That’s always the goal.

What are you prepared to do today?

        Dr. Chet

References:
1. Cell. 2019. DOI:https://doi.org/10.1016/j.cell.2019.07.047.
2. Cell. 2019. DOI:https://doi.org/10.1016/j.cell.2019.07.049.
3. Cell. 2019. DOI:https://doi.org/10.1016/j.cell.2019.07.050

Fasting and Memory T Cells

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The second paper from the journal Cell on fasting examined the longer term effects of fasting on memory T cells. Several species of mice were used in a variety of studies; these were complex experiments to say the least. Before I go further, a little about memory T cells.

Memory T cells are a class of T cells that remain after responding to a prior infection; they’re also created in response to vaccinations. The benefit is that if someone is re-exposed to the same or similar pathogen or toxin, the memory T cells mount a more vigorous attack than after the first exposure.

The mice were monitored for two weeks to establish a baseline caloric intake, then they were maintained on 50% of their caloric intake for three weeks or longer. There were several experiments. In some, while the calories were reduced by 50%, protein, vitamins, minerals, and essential amino acids were maintained at 100%. Therefore, there were no micronutrient or protein deficiencies, just calorie deficits.

The researchers found that stress hormones increased in response to caloric reduction. The memory T cells were transported and stored in the bone marrow. When the diet was returned to normal, the memory T cells were returned to their typical locations in the immune system. Other experiments showed that the memory T cells had an enhanced ability to fight pathogens.

One more study to examine on Saturday.

What are you prepared to do today?

        Dr. Chet

References:
1. Cell 2019. DOI:https://doi.org/10.1016/j.cell.2019.07.049.
2. Translational Biology in Medicine, 2014.