Tag Archive for: metabolism

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.

Metabolism Across Our Lifespan

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It might not surprise you to learn that adjusted for body weight, infants under one year have the highest metabolism of all age groups. It makes sense; they’re growing so fast at that point. From there it’s all downhill, metabolically speaking, at a rate of about 3% per year until about 20 when metabolism stabilizes. The lowest metabolism? We reach that sometime after 60. If we live to 90, researchers found that caloric needs declined by 26%.

That’s the “what.” More important is the “why”; researchers had some but not all of the answers.

Metabolism and Life Events

Researchers examined metabolism during adolescence. The expectation is that metabolism would increase during this period of growth, but they found that it didn’t change significantly.

There was also no significant increase in metabolism during pregnancy, at least, more than what was expected. In Healthy Babies, I talk about the caloric needs of pregnant women by trimester. Those caloric needs prove to be spot on. Sorry, but there’s no need to eat for two.

One more point: carrying extra fat results in an increase in metabolism. That makes sense because every extra pound means the muscles work harder in moving the weight, the heart pumps harder because there are more blood vessels, and so on. But when extra body fat is accounted for, there’s no difference in metabolism on a pound-for-pound basis.

Why Does Metabolism Decline?

Why does our metabolism start to decline faster at around 50 or 60? One factor is the loss of muscle mass; that’s why it’s so important to increase muscle mass and hang on to it as we age.

This study measured caloric use over 24 hours, so the age-related decline in physical activity may play a role in why metabolism declines: most of us are much less active over 50.

But one of the many researchers involved in the projects stated it this way: the reason for the decline in metabolism is that “cells are slowing down.” He went on to say that these changes occur in ways we don’t yet understand. Do the cells get tired? Have a harder time with cell division? Or are there some as yet unknown signal chemicals that are controlling the aging mechanisms that impact metabolism? We don’t know yet.

The Bottom Line

One study is not enough to find out all the answers to what happens to metabolism as we age, but it does provide some insights in where we can look to find the answers. One area that might be interesting is the mitochondria, the powerhouse of the cell; what happens there impacts our ability to make energy and that can definitely impact metabolism. We’ll keep an eye on this research as time goes on.

What are you prepared to do today?

        Dr. Chet

Reference: Science 13 Aug 2021. 373 (6556):808-812. DOI: 10.1126/science.abe5017

What Happens to Our Metabolism?

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Have you ever said or heard someone else say, “I could eat whatever I wanted when I was young and I never gained weight!” What usually follows is something like, “Now I seem to gain weight just by thinking about a donut!”—the type of food may vary depending on the individual. Kids seem to eat anything they want and stay rail thin. Riley grew five inches between his five-year and six-year physicals but gained only three pounds. The logical question is what happens to metabolism as we get older?

Researchers in the Pennington Biomedical Laboratory attempted to find out together with researchers from around the world. As a combined effort, they recruited over 6,000 subjects between the ages of six months and 95 years old. The reason they needed so many research facilities is that the technique used to assess metabolism is labor intensive; it would have taken a decade for a single facility to do it. They didn’t test only resting metabolism. They were able to test the metabolism of subjects over several days under a variety of everyday conditions—in other words, people just living their lives.

There was no surprise from the aging perspective: metabolism declines as we get older. But when metabolism peaks and when it declines the most was surprising. I’ll cover that on Saturday as well as what we might be able to do to deal with it.

Tomorrow night is the Insider conference call. If you have questions you need answered about nutrition, supplements or exercise, this is the forum to get the most complete answers. If you’re not an Insider, join before 8 p.m. Eastern to participate.

What are you prepared to do today?

        Dr. Chet

Reference: Science 13 Aug 2021. 373 (6556):808-812. DOI: 10.1126/science.abe5017

How the Quality of Your Diet Changes Your Mycobiome

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In the experiment I told you about on Tuesday, the researchers established that environment—exposure to light, temperature, and other environmental factors—affects the microbiome, including the fungi or mycobiome. The researchers then tested the changes in the mycobiome (the fungus part of the microbiome) after feeding the mice a highly processed diet compared with mice eating conventional mice chow. They also monitored changes in body composition, triglycerides, and other hormones related to obesity.

After eight weeks on the highly processed diet, there were differences in the quantity of fungi. Some groups of related organisms increased while others decreased. Because not every group has known roles in digestion and metabolism, the researchers examined metabolic changes in response to the dietary change; they found an increase in body fat and triglycerides in the male mice along with concurrent changes in hormones that signified a move toward prediabetes. (For some reason, the female mice in this species are protected from those effects.)

After examining the composition of the highly processed chow, I’d like to have seen one more group of mice in the experimental group. Because the highly processed chow had no fiber, it would have been helpful to see what would happen to the entire microbiome if the amount of fiber was the same in the processed chow as the conventional chow. Maybe it wouldn’t have impacted the fungi at all, or the change could have been significant.

The Bottom Line

What lessons can we learn from this study? We’re not mice after all. I think it means that a highly processed, highly-refined carbohydrate diet may cause undesirable changes in our microbiome, including the fungal levels as well. For example, Candida albicans is a primary fungus in our digestive system, but it can cause all kinds of problems if it gets out of control. Reducing refined carbohydrates has a beneficial impact on keeping that fungus at beneficial levels.

Regardless of your current age, a better diet is part of Aging with a Vengeance. Reducing processed food, especially carbohydrates, can benefit your microbiome and all that it impacts. Time to start now.

What are you prepared to do today?

        Dr. Chet

Reference: Comm Bio (2021).4:281 https://doi.org/10.1038/s42003-021-01820-z

Does Carbon Dioxide Affect Nutrition?

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Carbon dioxide is a waste product of energy metabolism. When we burn the food we eat, the protein, carbohydrates, and fat will be eliminated as carbon dioxide and water. When we use the gasoline in our cars or lawnmowers, CO2 and water are also released during that form of metabolism (called combustion) as well. The benefit for us and our cars is that we get energy. The problem is that we’re producing too much CO2 from gasoline and other fossil fuels.

CO2 levels have risen and fallen over the millennia in response to global trends, but since the invention of the internal combustion engine, the atmospheric CO2 levels continue to rise. As the number of uses for engines has increased, so have CO2 levels; they’re now 100 ppm higher than the previous highest level.

What does this have to do with nutrition? After all, don’t plants need CO2 for photosynthesis? They combine CO2 and H2O together to make sugar, right? Correct. But what researchers wanted to know is whether the excess CO2 would affect the nutrient content of specific crops. Are we growing supercrops? That could have immense implications for global nutrition. I’ll talk about what they discovered on Thursday.

What are you prepared to do today?

Dr. Chet

 

Reference: https://go.nasa.gov/2zkpdjL.

 

What Your Thyroid Does

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A common question: “I’ve just been diagnosed with an underactive thyroid. What can I do? I don’t want to take medication. I want a natural solution.” Usually, there’s a spicy descriptor that precedes the word medication. In response, the Memos this week are about the thyroid: What does it do? What happens if it doesn’t function properly? What are the treatment options?

The thyroid gland is a butterfly-shaped gland that resides on the front of the neck just above the collarbone. The best word to describe what the thyroid does: metabolism. How does it do that? By producing the hormones thyroxine (T4) and triiodothyronine (T3). It’s actually an elegant process that includes the hypothalamus and pituitary glands. The hypothalamus monitors the blood for status reports. When it senses a need for an increase in thyroid hormones, it signals the pituitary and the pituitary releases thyroid stimulating hormone (TSH), which tells the thyroid to increase the release of hormones.

Back to metabolism. That’s the rate at which cells function from calories burned, heart rate, muscle growth and repair, and many other processes. If the thyroid starts to fail, it can wreak havoc just about everywhere in your body. That’s what we’ll talk about on Thursday.

What are you prepared to do today?

Dr. Chet

 

The Bottom Line on Weight Loss Supplements

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In the weight loss supplement debate, who is correct: proponents or opponents? Are any weight loss supplements beneficial? The answer is complicated.

The opponents of weight loss supplements have the bulk of research on their side for two primary reasons. Weight loss studies using dietary supplements have a lack of consistency in the form of the supplement used, the combination of nutrients in the supplements, and the methodology. That can include everything from the amount of the key ingredient being examined to the number of subjects in the study. The second reason is that some studies examining weight loss supplements on humans don’t control for confounding variables such as age, menopausal status, gender, and type of diet and exercise used to lose weight.

That doesn’t mean that opponents of weight loss supplements have evidence on their side—just the lack of consistent evidence. The problem is a lack of research that demonstrates a significant and permanent impact on body weight. In addition, some weight loss supplements may have potentially negative side effects, so the opponents have the advantage.

Another reason for the opponents’ advantage is the overselling of weight loss benefits based on marginal research. Remember what I began these memos with: “The fat will melt away!” I wish that were true, but there’s no supplement that directly does that. Even if we go back to a banned weight loss supplement, ephedra, it didn’t burn fat. It helped control appetite and may have increased metabolism slightly. There are no safe dietary supplements that do that to any significant degree. Small studies in rodents or even test-tube studies show the potential benefit of many types of herbs, but there are few human trials.

The problem for those selling weight loss supplements is that the type of research that would satisfy the opponents will never be done—it simply costs too much money. While the weight loss supplement industry is a multi-billion dollar industry in total, no single product comes close to generating that kind of revenue. With the type of clinical trials necessary to satisfy critics, there would be no profitability, especially when any other company could put out a competing product with the same ingredient in a different dose and say it’s just as good.

Bleak picture? It depends on how you look at it. Let me give you my perspective.

 

My Take on Weight Loss Supplements

I’ve spent a considerable amount of time checking out weight loss supplements. Is the research perfect? No. But if a nutrient or herb has at least some positive outcome helping people lose weight, I’m fine with that. If it’s mostly theory and animal research with poor human trials, I let it go until they prove something. With that in mind, I think there are some supplements that have consistently shown a benefit in helping people lose weight. The reason they work is not always what is purported to be the reason. The results will be different for different users based on their genetics, their microbiome, and their environment.

So here goes. In my opinion, the weight loss supplements that have shown the most benefit helping people lose weight when they eat less and move more are:

  • Chromium picolinate
  • Garcinia cambogia
  • Conjugated linoleic acid (CLA)
  • Green tea extract

Why do I think these will help? For one reason: they give people an edge in their effort. They positively affect carbohydrate and lipid metabolism, may help increase overall metabolism, and help control hunger. They will never help people lose weight without diet and exercise, but they will give those who are trying an edge in their efforts. To me, that’s worth the cost. That’s why I use most of them myself.

The opponents of weight loss supplements offer nothing other than an opinion. To me, that may be intellectually correct but it’s morally corrupt. With 70% of the population overweight, we don’t need naysayers and obstructionists. We need alternatives that work.

What are you prepared to do today?

Dr. Chet

 

Sleep More and Quit Eating Sooner

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Sleep more, eat the same, and lose weight. Seriously? That’s what researchers are going to try to find out. At this point, there’s little question that for most people, lack of sleep messes with the circadian rhythms and negatively impacts glucose metabolism.

But a different research team is looking at another element: how long you eat every day can impact your ability to lose weight. Researchers have done a pilot study looking at eating intervals: the time you eat your first meal until you stop eating for the day. For people devoted to their evening snacks, it can be 16 to 18 hours per day.

In the pilot study, subjects restricted their eating to a period of 10 to 12 hours per day. Over 16 weeks, subjects lost an average of seven pounds. One more thing: they didn’t have to restrict their eating. They ate what they wanted, just in a shorter time interval every day.

This was a pilot study using an app that the researchers developed; they’re recruiting 10,000 subjects to see if the idea will work on a greater scale while collecting additional data. Such as what? Well, maybe you actually eat fewer calories when you eat in smaller time frame even if you eat the same foods. By the way, if you want to be a subject, check out www.mycircadianclock.org to see if you qualify.

Back to the sleep portion. The part that interests me the most is the messed up carbohydrate metabolism by eating when your clock says it’s time to sleep. Getting more sleep is not easy these days, but it just might be worth it.

We’ve all heard people say they cannot lose weight no matter what they do. Well, maybe getting a little more sleep and eating over fewer hours may help. Of course, if you’re a diabetic or hypoglycemic, talk with your doctor. But here’s something simple and cheap you could do: sleep more and eat the same over fewer hours. Will you lose weight? We don’t know, but it’s worth a try.

What are you prepared to do today?

Dr. Chet

 

Reference: doi:10.1001/jama.2017.0653

 

Can You Lose Weight by Sleeping More?

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That doesn’t seem to make any sense; you’re not going to be as active because you’re sleeping, so how can that help you lose weight? Well, if you’re sleeping you’re not eating, but there must be more to it than that. Let’s go back to the SCN, the pacemaker of rhythms.

Researchers have found that cortisol and melatonin aren’t the only hormones and organs tied to the light-dark cycles. Hundreds if not thousands of genes also respond to light-dark cycles. Glucose metabolism, the processing of sugars, is tied to these cycles; we seem to process sugars better during the light hours than at night. For some reason, eating carbohydrates in the dark hours results in slow processing of carbohydrates. Typically carbohydrate metabolism is a fairly high-energy process using 15 to 20% of the calories in digestion and absorption, but eating in the evening seems to decrease metabolism enough that it could theoretically result in gaining 12.5 pounds in a year.

Theory and life are two different things. Research on rodents shows that if researchers flip their cycle by feeding them in opposition to their rhythms—they’re day-sleepers, so they’re the opposite of us—they gain more weight when fed the same diet than mice fed during their normal cycle.

What about humans? Is there a solution? Skinny rats are fine, but what’s in it for us? We’ll wrap this up on Saturday.

What are you prepared to do today?

Dr. Chet

 

Reference: doi:10.1001/jama.2017.0653

 

Does Weight Loss Ruin Metabolism?

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The health headlines two weeks ago were focused on what we can call “The Biggest Loser Study.” Researchers published the results of a six-year follow-up of contestants in Season 8 of the reality show “The Biggest Loser.” It turns out that most contestants gained back a significant amount of weight. Why? Based on the research, decreased resting metabolism was identified as the most likely suspect. Headlines shouted that weight loss caused metabolic rates to fall more than expected and therefore made it hard, if not impossible, to maintain weight loss.

I believe that all research has merit, even . . .

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