Friday, April 15, 2016

Diet versus Exercise.... Which Holds The Key And Which Revs The Engine?


“Increased arterial stiffness…”

“Cardiovascular disease…”

It’s not uncommon to read or hear these three health issues scrambled together in the media, whether it’s a New York Times headline, a buzzworthy "need-to-know" article, or a trending Facebook post. Maybe you’ve seen a headline like this in the news lately…

“Obesity Linked To Stiffened Arteries and Cardiovascular Disease”

…and you think to yourself, “Well, duh!”

Or maybe you read a headline that offers an approach on to how to fix this, such as:

“Eating Less Junk Food and Jogging More Reduces Weight and Decreases Cardiovascular Disease Risk in Obese Individuals”

And then you think, “Well, double duh!”

After all of these "duh" moments, finally, the light bulb goes off and you then have an “hmmm” or “aha!” moment. That moment when you ask yourself, "Well, which is better: changing your diet or changing your exercise habits? What’s the answer?”

 I think we could all agree that changing both would be extremely beneficial; however, does one take presence over the other in specific situations, like when a person is obese and has stiff arteries?

Wait, hold up. Back it up. We are not all food nerds or doctors. Let’s start with the basics. What, exactly, is an artery? To visualize an artery, think of a small tube running through your body's circulatory system. Then picture your blood streaming through this tube, much like you would see if you’ve ever given blood or watched someone else give blood. Then imagine the walls of this tube are made of muscle. The main role of the arteries is to take oxygenated blood from the heart to the tissues in the body.

Think about that. The artery has a pretty important job. It's kind of a big deal. I don't know if I would want to be an artery. Or if I was, I would hope I’d be working for someone who takes good care of me, so I could score the biggest bonus at the end of the year... more quality years!

So back to what got me started on this artery description hiatus. For starters, stiff arteries are like rusty pipes. When you have rusty pipes, water doesn't flow as smoothly, and over time, when things get really out of shape, there could even be a backup due to pieces of the rusty metal breaking off the pipes into the water. Apply this to someone's arteries and it becomes downright dangerous.

So how do we fix this... or to pose a better question, how do we PREVENT this from happening? Well, unfortunately, it cannot be 100% fixed or prevented. However, the stiffening of arteries can be reduced and slowed by way of lifestyle factors—specifically, exercise and a healthy diet, both of which have been shown repeatedly by research studies. But which one is better, you ask? A group of researchers asked the same question. 

Faculty member Seiji Maeda and colleagues of Health and Sport Sciences at The University of Tsukuba, Japan  compared dietary modification and aerobic exercise training to see how it affected arterial stiffness, as well as the endothelial function in men who were overweight and obese (the endothelium is the inner lining of the blood vessels). Here is what you need to know:

·         45 overweight and obese men (with the average age of around 48) completed a lifestyle intervention.  26 men completed a dietary intervention and 19 completed an exercise intervention.

·         The dietary modification included a well-balanced diet of 1,680 calories a day.

·         The exercise program included walking 50—60 minutes a day, 3 days a week. 

·         Each intervention lasted 12 weeks.

The study produced interesting results:
  • Each participant’s Body  Mass Index (BMI) decreased with a significant different between groups, whereas those in the dietary intervention decreased their BMI to a greater extent.  BMI is a measurement based not on body fat percentage, but instead is an equation that takes into consideration height and weight only—which, when too high or too low, is associated with certain diseases and mortality (phew… that was a mouthful!).

  • Participants also decreased their waist circumference (WC), which specifically looks at the fat around the waist (the more dangerous, visceral fat).

  • In general, participants lost more weight after the dietary intervention as opposed to the exercise training intervention , as noted from the significant difference in BMI change between groups.

  • The participants’ arterial stiffness did improve after both dietary changes and exercise training; however, no significant improvements were seen between the two interventions.

So… what does all this mean? Still not feel like you don’t really have a concrete answer? Welcome to the nutritional scientific research world! Each research study is one glimpse and one step closer to finding an answer, and sometimes that answer depends on the individual’s genetics or confounding variables. In the case of this particular study, it is safe to conclude that the obese men who were assigned to the exercise intervention (walking for an hour at least three days a week) may not have seen the scale budge as much as those who just ate a more balanced diet and didn’t exercise; however, their arteries gained similar benefits. In other words, health is not measured just by a scale, and I believe this to be a driving factor when I educate my own clients who come to me with a main goal to get to a certain weight. Some people may drop a couple of jean sizes but may not see that weight loss show up on the scale, because they gained muscles while burning fat during exercise, and muscle weighs more than fat. It’s a win-win situation!

I also want to emphasize that this does not mean you have the green flag to eat McDonald's every day as long as you "walk it off." No, absolutely not. This way of thinking will backfire and trick you into thinking that it’s okay to eat all the junk food you want, as long as you work out. Your body is smarter than you think and will quickly catch on.  If your speed is more “auto body” than “human body,” think of it this your body like a car: would you put Kool-Aid into your car's gas tank and expect it to get you where you want to go?  (Pretty soon, these cars will be outdated as we clear the road for electric cars and Teslas!)

In dietary intervention alone, participants improved in more areas than just arterial stiffness: they also lost more weight and reduced their waist circumference drastically, which means they also cut more of that dangerous visceral fat. Now, imagine what it would have been like if there had been a group who had completed both a dietary and an exercise intervention simultaneously. I suspect these subjects would have showed a significantly greater improvement in arterial stiffness, endothelial function, BMI, and WC versus the other two groups. Trust me, other people are guessing and testing the same hypothesis, and perhaps you yourself are living proof that this is true—your doctor tells you to exercise and eat better, you find professionals to help you do so, your doctor runs some blood tests, puts you on a scale, and then praises you for the improvements in both your cardiovascular health and your weight. 

So all of this probably seems pretty straightforward, right? It makes sense that exercise and diet modification would improve the health of these men who are overweight and obese. It's common sense, and common sense should never be underestimated. So here are my own takeaway points I want you to strap your knowledge belt as you strut down the street:

1) This study gives hope to anyone who has been instructed by a physician not to exercise due to any serious heart problems. Even if you are unable to work an hour of walking three days a week into your schedule, you can always change your diet. Working with a dietitian can help you do this one baby step at a time, and this may be the key to improve your biometrics, so your doctor gives you the go ahead to start an exercise program!

2) Keep in mind 12 weeks is a long time—3 months. These things do NOT happen overnight. However, they do happen, and taking it one day at a time, learning about diet and exercise may help you stick with it versus going at it in the long term without understanding exactly why you are doing what you are doing and how it will benefit you in the now and in the long run.

3) The researchers concluded that a combination of exercise and diet modification would yield the greatest benefits, and I agree. In my professional opinion, your diet is the key. It will jump-start your engine by fueling your body with plentiful nutrients. Exercise is the engine that will continue the fat burning, muscle building, and when that time comes, weight maintenance, not to mention other cool perks such as more energy and happiness.

 By working with wellness experts as well as finding your own intrinsic motivation (do it for your health, your kids, your family, or for that wedding dress), we all have to start somewhere, and the most influential person who will help you stick with these healthy habits is... yourself.

Kelly Ahearn, MS RDN CDN is the owner of Indigenous Nutritionist, a private practice and consulting startup based in NYC. She has partnered with Running This World to offer nutritional education sessions via tele-health for anyone who registers for the complete package at


Seiji Maeda, Asako Zempo-Miyaki, Hiroyuki Sasai, Takehiko Tsujimoto, Rina So, Kiyoji TanakaLifestyle Modification Decreases Arterial Stiffness in Overweight and Obese Men: Dietary Modification vs. Exercise Training 2015,25, 69-77

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