Dr Parr Says…

Macronutrients—carbohydrates, proteins, and fats—are the three main nutrients that provide energy and are essential for maintaining overall health. Each macronutrient plays a specific role in bodily functions, from providing energy to supporting growth and repair. Understanding the importance of macronutrients in the diet is key to achieving optimal health. I explore the roles of carbohydrates, proteins, and fats, as well as recommended intake levels in my Health & Fitness column in the Aiken Standard this week.

Carbohydrates are the body’s main source of energy. They are broken down into glucose, which is used by cells for energy or stored in the liver and muscles as glycogen for later use. Carbohydrates can be classified as simple (sugars) or complex (starches and fibers). Complex carbohydrates, such as whole grains, fruits, and vegetables, are particularly beneficial because they provide sustained energy and are rich in fiber, which aids digestion and supports cardiovascular health.

According to the Dietary Guidelines for Americans, 45-65% of daily caloric intake should come from carbohydrates. For example, in a 2,000-calorie diet, this would equate to 225-325 grams of carbohydrates per day. Emphasizing fiber-rich, complex carbohydrates and minimizing refined sugars is key to maintaining healthy blood sugar levels, important for preventing and treating conditions like obesity and type 2 diabetes.

Protein is essential for the growth, maintenance, and repair of tissues. Proteins are made up of amino acids, some of which are essential, meaning they must be obtained through the diet. Protein plays a critical role in producing enzymes, hormones, and other chemicals in the body. It is also involved in immune function and supports muscle growth and recovery, especially for those who engage in regular physical activity.

The Recommended Dietary Allowance (RDA) for protein is 0.8 grams per kilogram of body weight for the average adult, which equates to approximately 56 grams per day for a 70 kg (154 pound) person. However, protein needs vary depending on factors such as age, activity level, and overall health. For example, athletes, pregnant women, and older adults may require more protein to meet their specific needs. A more reasonable protein intake for most adults is probably 1.2 grams per kilogram of body weight, or 84 grams of protein for a person who weighs 154 pounds.

Dietary fats are crucial for good health. Fats provide energy, aid in the absorption of fat-soluble vitamins (A, D, E, and K), and are vital for cell membrane integrity. Fats are also essential for hormone production and brain health. Fats are categorized into saturated fats, unsaturated (including monounsaturated and polyunsaturated) fats, and trans fats.

While some fats are beneficial, such as those found in avocados, nuts, seeds, and fatty fish, others, like trans fats and excessive saturated fats, can increase the risk of cardiovascular disease. The Dietary Guidelines recommend that fats make up 20-35% of total daily calories, with the emphasis on consuming more unsaturated fats and limiting saturated and trans fats. For example, in a 2,000-calorie diet, this would translate to 44-77 grams of fat per day.

Balancing the intake of carbohydrates, proteins, and fats is crucial for maintaining overall health. Different macronutrient distributions may be recommended based on specific goals, such as weight management, athletic performance, or managing a medical condition. For instance, a higher protein intake is often recommended for those aiming to build muscle, while individuals managing diabetes may benefit from a lower carbohydrate intake with a focus on complex, high-fiber carbohydrates.

Macronutrients play essential roles in supporting bodily functions, from providing energy to facilitating growth and repair. Carbohydrates are the body’s primary energy source, proteins support tissue repair and immune function, and fats are crucial for hormone production and cellular health. Achieving a balanced intake of these macronutrients, tailored to individual needs, is key to maintaining optimal health and well-being. By emphasizing nutrient-dense sources, individuals can support both their short-term goals and long-term health outcomes.

 Do you need to exercise every day? Or could you exercise on just a couple of days instead? According to one of my favorite studies, saving your exercise for the weekend can give you the same health benefits as spreading your exercise out over multiple days. However, becoming a “weekend warrior” might not be the best approach for you. This is the topic of my Health & Fitness column in the Aiken Standard this week.

Current physical activity recommendations call for us to accumulate 150 minutes per week of moderate-intensity activity or 75 minutes per week of vigorous activity. Typically, this would be done on multiple days per week (walking 30 min per day on 5 days, or jogging 25 minutes on 3 days). This study answers an important question about physical activity and health—can you get away with only exercising a couple of days per week instead of the recommended 3–5 days? It also included people who do some, but not enough, activity throughout the week.

This study looked at how physical activity pattern was linked to the risk of death from all causes, cardiovascular disease (CVD), and cancer, a common way of examining the effect of physical activity on health in large populations. The study compared the risk of death among four physical activity pattern groups: inactive, insufficiently active (some activity, but not enough), regularly active (meeting PA recommendations throughout the week), and weekend warriors (meeting recommendations in just 1-2 days per week).

The results show that, compared to the inactive group, the risk of death was lower in the insufficiently active, regularly active, and weekend warrior groups. This was true for deaths overall as well as deaths from CVD and cancer. Furthermore, the reduced risk was similar for the three activity patterns, but lowest in the regularly active participants.

This confirms what we already knew from numerous other studies: regular physical activity promotes longevity. The study also suggests that being active throughout the week, but not enough to meet those recommendations, is also associated with some reduction in risk. We knew that, too. What this study adds is that meeting the recommendations by doing the activity on 1–2 days, the “weekend warrior” pattern, is beneficial, too. In fact, this activity pattern seems to be about as good as being active most days of the week. This is good news for people who aren’t active on a daily basis!

That said, this study only examined mortality, meaning the number of people who died during the follow-up period. It doesn’t tell us much about how these activity patterns affect health the way most of us would consider it: controlling blood pressure, diabetes, blood lipids, or depression. It also doesn’t say anything about weight control or improving strength, endurance, or flexibility, which are important reasons many people are active. In both cases, exercising regularly is the key to realizing the benefits!

Additionally, the typical “weekend warrior” tends to engage in exercise that is more intense and/or longer duration than what they might do if they exercised regularly. Indeed, the study indicates that almost all (94%) of the weekend warriors played sports and relatively few (31%) walked for exercise. While this is fine for most people, participating in vigorous, prolonged exercise can lead to a greater risk of injury, especially in people who aren’t in good shape to begin with.

So, people who are weekend warriors should select activities they will enjoy, and focus on duration over intensity. A long walk, hike, bike ride, or kayak trip on the weekend is something most people can do without too much risk. But the best approach is to be active throughout the week as much as possible and use weekends for more ambitious exercise sessions.

School is back in session in our area, marking the unofficial end of summer. But high temperatures and humidity mean that summer weather is still with us. Aside from being unpleasant, these conditions can be dangerous, especially for people who are active outdoors for work or exercise. This is the topic of my Health & Fitness column in the Aiken Standard this week.

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You may not know this, but May is Active Transportation Month, so this is a good time to be mindful of things we can do that are good for our health and the health of our planet. Active transportation, which includes walking, cycling, and other physically active modes of moving from place to place, is one example.  This is the topic of my Health & Fitness column in the Aiken Standard this week.

Active transportation has important environmental, health, and economic benefits for individuals and communities. Promoting active modes of transportation can reduce pollution, increase physical activity, and benefit both people and communities economically. In some areas, active transportation can replace motor vehicle use entirely. More commonly, though, physical activity can be combined with cars or public transportation to replace parts of trips.

Significant and accumulating evidence shows that motor vehicle use is a primary cause of air pollution. This includes greenhouse gasses like carbon dioxide and pollutants such as nitrogen dioxide, ozone, and particulate matter that are released by combustion engines and industry. This has been linked to climate change and health problems, including pulmonary and cardiovascular diseases, contributing to 200,000 deaths per year.

The transportation sector is the largest greenhouse gas emitter in the United States, so physically active modes of transportation that replace motor vehicle use could have a significant impact on air pollution and health. Estimates suggest that even a small decrease in vehicle miles traveled, a measure of motor vehicle use, by increasing active transportation could lead to reductions in particulate matter and greenhouse gas production.

In addition to environmental benefits, increasing active transportation has clear health benefits. As you might expect, spending more time commuting in a car is associated with an increased risk of obesity and more active commuting is associated with a lower risk of obesity. Beyond the influence on body weight, people who use physically active modes of transportation have a lower risk of diabetes and hypertension as well as death from cardiovascular diseases.

People who engage in active transportation get an average of 12–15 minutes of physical activity per day and 30% meet the 30 minutes per day recommendation. Considering that over a quarter of trips are less than 1 mile and most are less than five miles, most people could replace at least some driving with walking or cycling.

The cost of implementing active transportation is often cited as a reason not to, but individuals and communities can benefit economically from increased active transportation. Transportation represents the second largest expense for American families and may have a greater impact on low-income households. Given that active transportation is almost always more affordable than using a car, this could help many people and families make ends meet. 

Communities that develop infrastructure and policies to promote active transportation experience direct and indirect benefits. These benefits include increased residential and commercial property values as well as the fact that people who are walking or cycling are more likely to visit businesses along their route. Depending on the location and nature of the project, implementing active transportation can have a positive cost-benefit ratio and promote job creation.

Given the environmental, health, and economic benefits, active transportation is a win, win, win for our community. Across the country, cities large and small are implementing infrastructure and policies to make them safer and more convenient for pedestrians and cyclists. Since everyone benefits from a community that supports active transportation for work and leisure, we should take steps in that direction.