“Heart” your heart.

Today is World Heart Day, with a focus on encouraging all of us to make heart-healthy choices to reduce cardiovascular disease risk. I thought that sharing some information about the heart, how it works, and how to keep it healthy would be an appropriate way to celebrate. This is also the topic of my Health & Fitness column in the Aiken Standard this week.

Your heart started beating months before you were born and will continue to beat every second or so…until it stops, signaling the end of your life. During your lifetime, your heart will probably beat more than two billion times, or about 100,000 times per day. (more interesting heart facts here)

The major function of the heart is to pump blood to all of your tissues through the arteries and back again through the veins. The heart has four chambers: the left and right atria that receive blood from the veins and the left and right ventricles that pump blood into the arteries. The right ventricle pumps blood to the lungs to pick up oxygen and the left ventricle pumps oxygenated blood out to the rest of the body.

The activity of your heart will vary throughout the day. At rest your heart rate is low, typically around 70 beats per minute. Some athletes have resting heart rates that are much lower, owing to their bigger, stronger hearts.

But when you are active your heart beats faster and more forcefully to eject more blood to the working muscles. During intense exercise, a young person’s heart rate can go above 200 beats per minute and the amount of blood pumped can be five times higher than at rest!

The heart is made up mostly of muscle that functions similarly to the skeletal muscles you use to move your body. But cardiac muscle is different in that it can spontaneously contract when stimulated by a specialized area of the heart called the SA node or pacemaker. And unlike skeletal muscle, the heart is remarkably fatigue-resistant, meaning that it can contract repeatedly without needing a break.

In order to beat continuously, the heart needs a steady supply of oxygen which is delivered through coronary arteries, not from the blood inside the chambers of the heart. Normally, plenty of oxygenated blood gets through. But if the coronary arteries become narrowed through atherosclerosis, the accumulation of plaque in the vessels, blood supply can be limited.

This can lead to reversible symptoms like angina pectoris (chest pain), especially during exertion. If a clot forms in the narrowed vessel, blood flow can be blocked completely causing a myocardial infarction (heart attack). Heart disease can be managed using medications, angioplasty, or bypass surgery, but the best approach is to prevent the problem from occurring in the first place.

Taking care of your heart is one of the most important things you can do for your health. Like other muscles, regular exercise can make your heart larger and stronger to pump blood more effectively. Exercise also lowers your blood pressure and can help reduce your blood cholesterol, further reducing the risk of heart disease.

A diet that is low in salt and unhealthy fats, like trans fats, can help lower blood pressure and cholesterol, slowing the process of atherosclerosis and preventing heart failure, a condition in which the heart muscle becomes weak. Maintaining a healthy body weight and controlling blood glucose are also keys to a healthy heart.

More than anything, though, your heart likes to be active. So celebrate World Heart Day by taking your heart for a walk!

 

Loosening our belts. Expanding waistlines means expanding health problems.

In a report published this week, researchers showed that the waistlines of Americans are still expanding. This is bad news, since excess fat, especially around the waist, has serious implications for our health. Fortunately, there is much we can do to lose weight and improve our health.

This is the topic of my Health & Fitness column in the Aiken Standard this week.

The study, published in the Journal of the American Medical Association, looked at the percentage of adults who had a high waist circumference (over 35 inches for women and over 40 inches for men). Overall, the average American added over one inch to their waist circumference over the past decade. As of 2012, over half of U.S. adults (51%) meet the criteria for abdominal obesity, compared to 46% in 2000.

Since excess muscle tends to compress the abdomen, this really does reflect an increase in fat around the waist, not the benefits of a national sit-up campaign. And it is the location of the fat that makes this worrisome. Excess fat around the waist includes both subcutaneous fat beneath the skin (what you can pinch) as well as visceral fat stored deep in the abdomen.

Excess visceral fat is associated with an increased risk of high blood pressure, type 2 diabetes, and heart disease, among other chronic conditions. The only way to determine how much visceral fat a person has is through an imaging test like a CT scan. (In my lab we can estimate visceral fat by making a few abdominal measurements.) The important point is that the bigger your waist circumference, the more visceral fat you likely have.

You may have heard of people’s body shapes described as “apple” or “pear.” Upper body obesity (apple), sometimes called android obesity because it is more common among men, is associated with a high waist circumference and visceral fat. Lower body, or gynoid, obesity (pear shape) tends to involve a narrower waist but more fat storage in the hips, thighs, and buttocks.

These body shapes become apparent when you measure both waist and hip circumferences. A high ratio between waist and hip measurements indicates more upper body fat; a low waist-to-hip ratio suggests lower body fat. That said, just measuring your waist circumference can give you the same information. A waist measurement greater than 40 inches for men and 35 inches for women indicates excess upper body—and visceral—fat.

There is no single explanation for why waist circumference has increased so much in the population. But it almost certainly has to do with a combination of individual factors including what foods we eat, how much we eat, and how active we are. The average American with an expanding waistline likely eats too much poor quality food and doesn’t get enough exercise.

These are exactly the same factors that, when reversed, can lead to fat loss. Indeed, research shows that even modest weight loss from a low-calorie diet and exercise can result in reduced body fat, including visceral fat. This is one reason why weight loss is effective for reducing high blood pressure and controlling blood glucose.

Even if you don’t lose weight, increasing your level of physical activity, particularly regular exercise, can offset some of the negative health effects of excess visceral fat. In addition to helping you lose weight, exercise can also help you maintain your waistline and prevent abdominal obesity.

The bottom line is that when your pants start to feel tight, they are trying to tell you something. Listen to them!

Fat still matters

Last week I wrote about some recent research suggesting that low-carbohydrate diets may be better for weight loss that low-fat diets. For many, this study reinforced the notion that traditional recommendations are wrong and that the key to good health is to eliminate carbohydrates from your diet. This couldn’t be further from the truth.

The recent study did show that people lost more weight and experienced beneficial changes in blood lipids when they followed a low-carbohydrate diet compared to those who ate a low-fat diet. However, this does not mean that low-fat diets aren’t effective for weight loss or that they are “unhealthy.”

In fact, low-fat diets have long been used effectively to promote weight loss, reduce heart disease risk, and lead to healthier eating in general. This is supported by the results of hundreds of research studies as well as the practical experience of health professionals and real people. Here are two reasons why fat still matters when it comes to health.

First, reduced-fat diets have been shown to improve blood cholesterol and lower the risk for heart disease. Eating a diet low in fat, especially saturated and trans fat, has been the foundation of nutrition recommendations for decades. The fact is that these diets are effective for weight loss, reducing cholesterol, and otherwise improving heart health.

One famous study demonstrated that following a low-fat diet contributed to a reduction in the severity of atherosclerosis, the narrowing of arteries that leads to many heart attacks. Literally hundreds of other studies have shown similar beneficial results.

This isn’t some magical effect of eating less fat, though. The health benefits are likely due to eating more vegetables, fruits, and whole grains as much as they are to reducing fat intake. The point is that adopting a low-fat diet can lead to better nutrition overall.

Second, reducing fat intake is a good way to reduce calories. This is true because fat contains nine calories per gram, more than twice that of carbohydrates and protein, so cutting fat is an effective way to cut calories. Limiting fat intake also reduces calories indirectly because many high fat foods are also high in sugar and calories (think of most desserts).

It is important to mention that simply reducing fat intake won’t always lead to weight loss; total calories must be lower, too. This is a mistake many make when they reduce fat intake, but increase the amount of calories from other sources, typically carbohydrates. Many low-fat foods are actually relatively high in calories due to added sugar or people tend to eat more of them (the SnackWell Effect).

The effectiveness of low-fat diets for weight loss has been demonstrated in research studies (like this one) and countless weight loss programs. In one notable study, a diet low in fat even led to weight loss in people who weren’t trying to lose weight. And don’t forget that in the recent study about low-carbohydrate diets, the subjects that followed the low-fat diet also lost weight.

For some people, cutting carbohydrates as a way to lose weight is reasonable; for others, reducing fat intake makes sense. For most people, though, doing both to some extent is the best option, but going to extremes is unnecessary.

Eating less added sugar and avoiding foods with added fats (such as French fries) are good recommendations for almost everyone. That said, there is little evidence for the benefit of limiting carbohydrates in the form of whole grains, legumes, vegetables, and fruits or the fat in meat and dairy.

The bottom line is that the quality of food we eat is more important than the specific amounts of the nutrients it contains. Eating low-carbohydrate or low-fat diets can help steer you toward making healthier choices, but so can avoiding processed foods in favor of wholesome, nutrient-dense “real” food.

Good sources of protein for your low-carb diet

Thanks to a recent study and media coverage (including me), low-carbohydrate diets are a popular topic of discussion. For many people, cutting back on carbohydrates is a good way to reduce calories to promote weight loss.

Most low-carbohydrate diets also emphasize protein intake. But finding healthy protein sources is important for promoting weight loss and good health.

This recent discussion about the best protein for optimal weight loss  on the Train Your Body show on RadioMD should help.

The diet wars continue

If you are confused or frustrated by the conflicting claims about whether a low-fat or low-carbohydrate diet is the best, you are forgiven. First we were told that eating a low-fat diet was the best way to lose weight and improve heart health. Then, research suggested that low-carbohydrate diets were better. And back and forth it has gone for years.

During this time, the prevailing recommendations have suggested that a diet low in fat and high in carbohydrates was best. But more and more research has supported the notion that cutting carbohydrates, not fat, would lead to greater weight loss. Although this has been supported by some research, critics pointed out that eating more fat would raise blood cholesterol and other risks for heart disease.

According to a recent study, though, low-carbohydrate diets seem to have benefits for promoting weight loss and improving some indicators of heart health over low-fat diets. But you should hold off on shunning fruits and vegetables in favor of cheeseburgers! Here is a practical interpretation of the research and some common sense recommendations, taken from my Health & Fitness column in the Aiken Standard this week.

The study, published last week in the Annals of Internal Medicine, reported on 150 men and women who either restricted the amount of carbohydrates or fat they ate. After one year, the group that ate a low carbohydrate diet lost over 7 pounds more than the subjects on the low-fat diet. Additionally, the low-carbohydrate diet promoted greater improvements in blood lipids than the low-fat diet.

This is important for two reasons. First, this wasn’t a weight loss study; the researchers were simply following the subjects to see what would happen as they followed either diet. The fact that the low-carbohydrate group lost more weight suggests that it is relatively easier to cut calories following this type of diet.

This is consistent with other research showing that eating more carbohydrates, especially refined carbohydrates and sugar, can actually make people feel hungrier and eat more. Indeed, other studies have shown low-carbohydrate diets to be more effective for weight loss than low-fat diets (although a more recent study suggests there isn’t such a difference).

Second, the greater decrease in triglycerides and “bad” LDL cholesterol and increase in “good” HDL cholesterol in the low-carbohydrate group were different from what might be expected. Conventional wisdom holds that a low-fat diet should have a greater effect on blood lipids. Since weight loss can have a big effect on blood lipids, the improvement in the low-carbohydrate group may be due to losing more weight, not a direct effect of the diet.

It is important to note that the low-fat diet also led to weight loss in this and numerous other studies. The critical component of any weight loss diet is that it is relatively low in calories, regardless of what nutrients supply those calories. Really, almost any diet will lead to weight loss as long as it contains less energy than what is expended, but a low-carbohydrate diet may be more effective for weight loss than the traditional low-fat diet.

The bottom line is that the best diet is one that emphasizes eating wholesome foods, not on cutting carbohydrates or fat. That said, limiting carbohydrates in the form of refined grains and added sugar is an excellent way to reduce calorie intake and improve the overall nutritional value of what you eat. And shifting toward more monounsaturated fats (think olive oil and nuts) rather than worrying about the total amount of fat you eat is also a good idea.

Being mindful of eating habits, according to Shannon.

I had an interesting conversation with my friend Shannon earlier this week that fit with the topic of being mindful of health habits. (I have written about Shannon previously, but not for some time) 

She was telling me that one recent evening she drove to three fast food restaurants to get dinner for her family. Apparently, she wanted food from a different place than her husband, neither of which worked for her kids. As they sat down at the dinner table she became mindful of how ridiculous this was.

First, she spent almost an hour driving to fetch the food. This was time she could have spent doing any number of things, including actually preparing a meal for her family. Second was the cost, including the food itself and the gas required to drive to three different restaurants. Third, looking at the food they were eating made her realize that it wasn’t healthy. In fact, their meal included no fruits or vegetables (beyond french fries) at all!

What struck me was that the quality of the food they were eating was the last thing Shannon mentioned to me, almost as a afterthought. What got her attention was the time and money she sent on the food. Cooking at home could have taken less time and certainly would have cost less. It would have been healthier, too.

At least they ate dinner together

 

Being mindful of eating habits, according to Shannon.

I had an interesting conversation with my friend Shannon earlier this week that fit with the topic of being mindful of health habits. (I have written about Shannon previously, but not for some time) 

She was telling me that one recent evening she drove to three fast food restaurants to get dinner for her family. Apparently, she wanted food from a different place than her husband, neither of which worked for her kids. As they sat down at the dinner table she became mindful of how ridiculous this was.

First, she spent almost an hour driving to fetch the food. This was time she could have spent doing any number of things, including actually preparing a meal for her family. Second was the cost, including the food itself and the gas required to drive to three different restaurants. Third, looking at the food they were eating made her realize that it wasn’t healthy. In fact, their meal included no fruits or vegetables (beyond french fries) at all!

What struck me was that the quality of the food they were eating was the last thing Shannon mentioned to me, almost as a afterthought. What got her attention was the time and money she sent on the food. Cooking at home could have taken less time and certainly would have cost less. It would have been healthier, too.

At least they ate dinner together