Memorial Weekend F&V Challenge

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It’s time to reveal the consumer of the largest variety of fruit and vegetables over the Memorial Day weekend, but before I do, a couple of comments.

If you would have typically eaten the vegetables and fruits anyway, good job. I know that readers who perceive themselves as eating enough servings were probably more likely to respond, but still, good job.

For those of you who went out of your way to add more vegetables and fruit, I hope you’ll continue to find a way to increase your typical intake.

For those of you who didn’t try, there is no question that eating more plant-based foods is healthier for you. Taking great supplements fills gaps, but it doesn’t replace eating food as well.

The winner for the largest variety of fruit and vegetable intake was J.B. with a whopping total of 28 different vegetables and fruits. There were a number of readers who hit 20, but 28 was tops. Great job! We’ll issue the challenge again for the 4th of July holiday weekend.

Insider Call Tomorrow

Omega-3 fatty acids have been in the news lately; recent research has shown an association with omega-3 intake and the development of atrial fibrillation. I’m going to look at this in detail to see if there’s anything there. I’m also going to answer Insider questions. For those of you who aren’t Insiders, you have until 8 p.m. Eastern to join and participate in the call at 9 p.m.

What are you prepared to do today?

        Dr. Chet

SIT to Get Fitter

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Here are the results of the study on sprint interval training or SIT. There was an 11% increase in max VO2 after the first cycle, reduced down to 6.4% after the second cycle, and finished at an 8% increase. Were the subjects fitter? Max VO2 notwithstanding, they absolutely were fitter. The reason we know that is because during succeeding sessions, their heart rates were lower for a given workload. They were working just as hard, but they didn’t need to use as much energy to do it.

Is there an explanation for the apparent dip in the max VO2 increase? I think the reason the results appear stymied was that they overtrained. Athletes do intervals of any type once, maybe twice per week. The subjects trained every other day for six weeks—and the max VO2 test is like another sprint training session. If someone were healthy enough and had the doctor’s permission, doing a sprint interval training session once every two weeks is enough. I know it sounds so easy: “It’s just 15 seconds! I get to rest for two minutes.” Trust me, with 30 years as a runner and an exercise physiologist: you get shredded every time you do it. You need complete recovery after that kind of session whether cycling, sprinting on a track, on an elliptical, or whatever.

The Bottom Line

I hope you’ve enjoyed the progression of these recent studies. From a walking program to get fitter and sustain muscle mass in exercising muscles, to the comparisons of bike HIIT intervals versus running HIIT intervals to sprint intervals to get fit a little faster, there’s something for everyone. Just make sure you have your physician’s approval to exercise at the level of each type before you begin.

What are you prepared to do today?

        Dr. Chet

Reference: Medicine & Science in Sports & Exercise. 56(5):876-884, May 2024.

Sprint Interval Training

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Keeping with the theme of using interesting training techniques from the last Memos on HIIT training, this next study took it one step further. The objective was to see how fast subjects could get fitter using a sprint interval training program.

I think I need to define some terms here. When we talk about getting fit, there are different types of fitness. There can be tests of strength like lifting the most amount of weight in a bench press. There can be tests of stamina such as how many push-ups a person can do. But when exercise physiologists talk about fitness in the classic sense, they mean how much oxygen your body can use at maximal levels. It’s called max VO2.

To test whether or not someone could become fitter in as little as two weeks and continue to increase their fitness level through the six weeks of a training program, researchers recruited a group of 18 sedentary men with an average age of 23; five subjects dropped out over the course of the study. The reason the researchers chose this particular research topic was because prior research had shown that the initial gain in fitness was not increased further with continued training.

While prior research had used 30 seconds of sprinting with four minutes of easy moving, the researchers chose 15-second intervals on a bike with two minutes of easy pedaling and rest before the next interval. After a physical including an ECG, the subjects were allowed to practice the sprint/rest cycle twice before the actual program began. There were three cycles of workouts that went like this: they began with the max VO2 test to determine the resistance in the sprints. Then in succeeding workouts scheduled every two days, the number of intervals per session began at 10 sprints, then two sessions at 12 repetitions, a session of 14 sprints, and finishing with eight sprints. Then the cycle repeated.

What did they find? Were they fitter? You bet they were, but I’ll save the details for Saturday.

Insiders, I’ve changed the conference call date from June 12 to June 19. Being an Insider allows you to get details that would be too time consuming in Memos. For example, I’m researching omega-3 supplementation in light of all the recent studies questioning its use. I want to find out what’s going on, and I’ll talk about it a week from Wednesday.

What are you prepared to do today?

        Dr. Chet

Reference: Medicine & Science in Sports & Exercise. 56(5):876-884, May 2024.

HIIT: Specific Fat Loss

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What were the results of HIIT training? The researchers found that there were reductions in overall weight as well as subcutaneous and visceral fat. What’s the difference? The fat just under the skin is subcutaneous fat; visceral fat is behind the abdominal muscles and around the internal organs and is more related to the development of cardiovascular disease and type 2 diabetes. There were no differences in the outcome variables with two exceptions:

  • Those who were in the running group lost a greater percentage of subcutaneous fat than the cycling group at 16.1% vs. 8.3%. The other difference was that positive changes in the microbiome were correlated with the loss of subcutaneous fat. Before you get too excited, the actual loss of subcutaneous fat was close to two pounds in the running group and about one pound in the cycling group. Still, ask your butcher for one pound of fat and see what it looks like. It’s a lot and probably worth the effort doing the HIIT program.
  • The other benefit was an improvement in some positive bacteria in the microbiome. It wasn’t associated with running or cycling; it was correlated with the loss of subcutaneous fat. It seems that visceral fat would show more benefit, but that wasn’t the case. Maybe someday we’ll find out why.

The obvious problem with doing a running HIIT program is that you have to be able to run—at least for 45 seconds. While my running is progressing slowly, I do intervals only while walking or riding the exercise bike. But running for 45 seconds? I can handle that.

Finally, while I was puzzled about the microbiome benefits, I also questioned why there was a difference between cycling and running when it came to the loss of subcutaneous fat. The researchers didn’t have a reason to explain it. I’ll give you my informed opinion: running integrates more of the core during the actual interval than cycling does. My hunch could be tested with sensors that detect the electrical activity of muscles, but that’s fine tuning that might not be necessary. As a scientist, I always want to know why, but that’s not important; it’s just important that it is.

We’ve seen that 30 minutes of moderate walking can prevent the loss of muscle and a HIIT running program can help lose subcutaneous fat in those who are overweight. How about getting fitter faster? Is that possible? Find out next week when we look at SIT training—and sitting does have something to do with it!

What are you prepared to do today?

        Dr. Chet

Reference: Med Sci Sports Exerc 2024 May 1;56(5):839-850.



HIIT and Fat Loss

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One of the “facts” exercise professionals will tell you is that there is no such thing as spot reduction; by that I mean you cannot target a specific area of your body, let’s say your abdominal area, and lose fat by doing a targeted exercise such as sit-ups or leg lifts. You can make the muscles underneath the skin stronger for sure, but there doesn’t seem to be any evidence that you can reduce the amount of fat in that area.

With 35 years of experience in the field, I would say that requires a qualified answer—it needs to be qualified with the word yet. There hasn’t been a study that proves that you can reduce fat in a specific area yet. Is it theoretically possible? Yes, I think it is. The problem is this: who would do the high quantity of exercise focused on one area long enough per workout session to do themselves any good? It may be that we’ve approached it all wrong by focusing on resistance exercise. Let’s take a look at another study that compared high-intensity interval training (HIIT) on a cycle ergometer versus a treadmill.

Researchers began with two questions. Is there any difference in the fat mass in specific areas of the body after training using a cycle ergometer (an exercise bike that measures the energy output of the cyclist) or a treadmill? In addition to that, is there any change in beneficial microbes in the microbiome after training?

Let’s take a look at what they did. Researchers recruited 16 men with a mean age of 54 and initial BMI of 29.9. After assessing initial fitness level, body fat, and body-fat distribution using the DEXA scan, and taking an initial stool sample for analysis of the microbiome, the subjects were randomly assigned to the bike or the treadmill. To make sure that there were no significant changes in diet, the subjects were required to maintain their typical diet and do seven-day diet records periodically during the study.

Think of this as intervals for the everyday exerciser. The HIIT bike program required them to do ten intervals for 45 seconds each at 80–85% of the maximal heart rate (MHR), and then a 90-second active recovery, or a HIIT running program which were nine intervals for 45 seconds at 80–85% of MHR and again with 90 seconds of recovery between intervals. They were to do this exercise under supervision three times per week for 12 weeks. The goal was to have all exercisers use the same number of calories during the workouts, whether cycling or running. The subjects were then retested to examine the differences if there were any. What did they find? I’ll tell you on Saturday.

What are you prepared to do today?

        Dr. Chet

Med Sci Sports Exerc 2024 May 1;56(5):839-850.

Spot Reduction? Maybe

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Researchers collected data from four prior studies that put a group of sedentary overweight and obese men and women on a walking program. To determine the distribution of muscle, fat, and bone, they took MRIs of their entire body. That gave the researchers not only the amount of muscle and fat mass, but exactly where that muscle and fat were located.

Once researchers assessed the fitness level of these subjects, they developed an exercise prescription for them that had them exercise at 60% to 75% of their maximal aerobic capacity for 30 minutes a session, five days a week, for six months. Their heart rates were monitored throughout the exercise session to make sure that they did not exercise above those levels; that also allowed subjects to increase the speed or grade of the treadmill as they got fitter. The subjects used a food log to track all the food they ate.

Results

Did the subjects lose some weight? Yes. Even though they were trying to maintain what they ate, they were using more calories in exercise than they had been, so they did lose some weight—in this case, just a little over two pounds in the exercising group. The controls actually gained about half a pound in the six-month study.

Now to the good stuff. The results of the MRI showed that there were definitely regional differences in skeletal mass and fat mass. As was expected, the exercising muscles, primarily the hips, thighs, and legs, saw maintenance of the skeletal muscle mass but a decrease in the fat mass. In the upper part of the body, there was a slight decrease in muscle mass in the arms and upper torso with a very slight decrease in fat mass compared to controls.

The Bottom Line

So what does this all mean? First, because the mean age was around 55, maintaining muscle mass is critical—this is the time of life when age-related muscle loss starts to occur.

Second, if this were confirmed in several clinical trials, it would mean that there should be a focus on weight training or aerobic training that utilizes the entire body. Elliptical trainers and recumbent cross trainers come to mind as something that would use both the arms and the legs, so that may be part of the solution. And from personal experience, I can say that dance classes can have a similar effect.

In order to preserve muscle mass, exercising all your muscles is important; 60 to 75% of maximal fitness would be classified as moderate exercise. That means you don’t have to kill yourself in order to obtain the benefits of regular exercise to your cardiovascular system. Add to that some weight training a few days a week, and you have your own prescription for sustaining muscle mass and maybe losing just a little bit of fat mass along the way. But what if I told you that you could increase the loss of fat mass, especially in your abdominal region, by changing up the intensity of your workouts for a few weeks? Next week’s Memos will look at that research.

What are you prepared to do today?

        Dr. Chet

Reference: MSSE. 2024. 56(5):776-782.

Is Spot Reduction Possible?

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One of the questions that I’ve thought about over the years is what happens to the skeletal muscle and fat mass in non-exercising parts of the body. If you’re a runner or a walker, what happens to your upper body? What happens to your lower body? Do you retain or even increase the muscles in your thighs and calves? Do you lose fat from your legs? How about your upper body? Do you maintain the muscle mass that you had, or do you lose some? What about the fat mass? Lose or gain?

When I was a graduate student, I ran the body composition laboratory. Over my years in the lab, I underwater weighed probably 5,000 people, from five-year-olds to 90-year-olds, from those who were underweight to morbidly obese, from tiny little gymnasts to a Big 10 hockey team. While underwater weighing was the gold standard at the time, it used some assumptions about the distribution of skeletal muscle, bones, and fat mass that weren’t as precise as they should be. These days, state-of-the-art is dual X-ray absorptiometry, which is called DEXA for short. But that doesn’t give us a precise analysis of body composition to answer those questions either.

We now have that technology in magnetic resonance imaging. Using MRI can begin to give us the answer to those questions about muscle and fat mass. Can you get rid of that stubborn belly fat? We finally may have some answers, and I’ll tell you about the latest research on Saturday.

Don’t forget to send me your list of vegetables and fruits you ate over the weekend—and remember the ketchup!

What are you prepared to do today?

        Dr. Chet

The Holiday Challenge

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I hope you all have a safe Memorial Day weekend. Here in the northern hemisphere, it’s the official kickoff of the summer season that ends with Labor Day. I alluded to a challenge, so let me lay it out for you: I want you to keep track of all the vegetables and fruit you eat beginning today.

Expand your horizons and try some new veggies. Challenge yourself to eat something other than Romaine or iceberg lettuce for salads, although they certainly count. Try arugula or bok choy, or switch it up and grill some radicchio. For this challenge, corn on the cob counts as a vegetable instead of a grain. Melon, tomatoes, berries of all types, as well as bananas and apples count. I may even try grilling avocado for the first time.

Need some ideas? Paula found this intriguing recipe online, and we’re trying it this weekend.

The goal is to increase your phytonutrient intake by a massive amount. Vegetables and fruit all have some nutrients you need, and the summer is the easiest time to get them. You can prepare them any way you want; grill watermelon or pineapple or caramelize onions for your burgers. The method doesn’t matter because cooking may change the form of phytonutrients but doesn’t destroy them. As I said in Tuesday’s Memo, condiments count. Ketchup, mustard, and relish—sweet or dill—all have specific phytonutrients in them.

Using the honor system, send me a list of everything you ate from these groups—just the names, not the amounts. For the person who gets the most, I’ll offer a free six-month Insider membership or the digital Optimal Performance program. Have fun, be safe, and I’ll be back next Tuesday.

What are you prepared to do today?

        Dr. Chet

Exercise Is Relative

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The title of this Memo is a concept that can be difficult to understand, especially when you read the studies I’m going to cover after the Memorial Day weekend. I’m going to talk about high intensity and even higher intensity exercise. What I don’t want to happen is for you to begin to read them, make a mental decision that you could never do that, and miss an opportunity to get fitter.

When I say exercise is relative, it’s relative to the physical condition you’re in right now. If you regularly complete 100-mile bike races, you’re in a different category than someone who does 20 minutes on an exercise bike with no resistance. If you’re 25, there will be a difference compared to someone who is 65. Bodyweight also plays a factor. You want the effort to be relative to your fitness level now. If you can’t run, maybe you can walk fast. If you can’t walk fast because of joint pain, perhaps you can ride an exercise bike. If all you can do is put on some music and boogie a little bit, that’s a start. The mode of exercise won’t matter; just the relative effort you put into it.

Keep that in mind as you read the Memos. As long as you’re cleared to exercise by your physician, you can try some of the higher intensity effort exercises to see if they can fit into your workouts.

In Friday’s Memo, I’m going to give you a challenge for the Memorial Day weekend. Without giving you too much information, ketchup, mustard, and relish do count. Count for what? Friday…

What are you prepared to do today?

        Dr. Chet

Where’s the Proof?

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A series of articles and studies published recently have called into question the use of statistics in examining large health databases. It’s especially pertinent to nutrition research because placebo-controlled trials are virtually impossible.

See if this sounds familiar: eating meat is associated with an increased risk of colorectal cancer. The “association” is calculated by considering variables that may impact the development of cancer and estimating the hazard of eating various quantities of meat. Recent articles have called into question whether enough variables are being considered, because only a few people decide what else could impact the development of cancer other than meat. Then the analysis is run and the results reported.

What if they didn’t pick the correct variables or enough variables that could impact cancer? What if they didn’t use the correct statistical methods to analyze the data? That could be why one study shows fish oil lowers the risk of cardiovascular mortality and another says it does not. Let’s look at an example.

“Ultra-Processed Food is Bad”

Eric Schlosser is an author and filmmaker who wrote Fast Food Nation and made the movie Food, Inc.; Food, Inc. 2 has come out recently. As a guest on Real Time with Bill Maher, he commented that ultra-processed food (UPF) is the leading cause of obesity and other diseases, but he offered no evidence to support that position. He suggested that it was the artificial ingredients found in UPF that make us crave them and eat them without restraint. Again, no evidence.

Several epidemiological studies have suggested that UPF is related to obesity. The question that remains is how? If it’s the artificial ingredients, how do they do that? By stimulating appetite? Or turning off satiety signals? Or some other mechanism?

That data isn’t collected in most large studies. When the researchers select variables that could impact the results, are they considering the correct ones? It makes a difference because at the end of these large observational studies, that’s the question that remains: How?

The Bottom Line

There is no conclusion at this point. That’s not usually my style, but this is complicated. There are too many observational studies and meta-analyses that are being used as the foundation of medical care and health and nutrition education, because as I see it the data are incomplete. For now, there are some changes we know will work and can prove: Eat less. Eat better. Move more.

What are you prepared to do today?

        Dr. Chet