Exercise and Weight Loss

Written by Dr. Steve Chaney on . Posted in current health articles, Exercise, Healthy Lifestyle, Lose Weight

Author: Dr. Stephen Chaney

exercise and weight lossAre you confused yet?  Just as you were starting to wrap your mind around the current consensus recommendations that we engage in 30 minutes of moderate intensity exercise 5 days/week, news stories are starting to appear saying that might not be enough exercise if you want to lose weight!

So how much exercise DO you need, and why is there so much confusion with exercise and weight loss?

Let me start by reviewing a couple of studies that appeared a few years ago on weight loss in middle aged, overweight women.

 

Exercise and Fat Loss

The first study looked at the effect of exercise intensity on abdominal fat loss over a 16-week period(Irving et al, Medicine & Science In Sports & Exercise,40: 1863-1872, 2008).

The women in this study were divided into three groups:the control group that just continued their normal exercise pattern (little or none), a group that engaged in supervised moderate intensity exercise 5 days per week, and a group that engaged in supervised, high intensity exercise 3 days per week and moderate intensity exercise the other two days.

The diet was identical for all three groups and the calories expended by exercise were also identical (the high intensity exercise was performed for shorter periods of time so that the calories expended were the same).

The results were striking. Weight loss was similar in the two exercise groups (calories do count). However, the women in the high intensity exercise group lost a significant amount of abdominal fat while the other two groups did not! As you may know, abdominal fat appears to be much more damaging metabolically than fat stores in other parts of our bodies.

 

Exercise and Weight Loss

woman runningThe second study looked at the effect of exercise duration on weight loss over a 24-month period (Jackcicet al, Archives of Internal Medicine, 168: 1550-1559,2008).

In this case the diet and the intensity of the exercise(moderate intensity) were the same. The difference was in the duration of the exercise. In this case the calories expended by exercise was not kept the same. The group that exercised for longer burned significantly more calories than those who exercise for a shorter time.

Again the results were striking. Only those study participants who exercised for at least 275 minutes/week (an average of almost 60 minutes a day for 5 days) were able to lose 10% or more of their weight and keep the weight off over a 24-month period.

 

How Much Exercise is Enough?

So what does all of this mean to you?

how much exercise is enoughWhen most Americans decide to shed a few pounds, one of the first things they think of is getting more exercise. After all, it’s much easier to walk around the block during lunch hour than to actually change what you are eating.

The question then becomes how much exercise is enough? Is the recommended 30 minutes a day of moderate intensity exercise 5 days per week enough?

If you actually work through the math, it is pretty easy to guess that it might not be enough. For example, a recent study looked at how much moderate intensity exercise would be required for a 155-pound woman to burn off the calories in same popular fast foods. For example, to burn off the calories:

  • In a MacDonald’s Big Mac, she would need to cycle at a moderate pace for 1 hour.
  • In an Arby’s Reuben, she would need to walk at a moderate pace for 3 hours.
  • In a Super Sonic Double Cheeseburger with Mayo, she would need to do low impact aerobics for 3 hours.

Of course, if she had fries and a soda with any of those meals she would need to do even more exercise.

weight loss and dietThese estimates are not just hypothetical. The studies described above clearly show that if you are relying on exercise alone to shed your excess pounds and/or excess fat, you are going to need higher intensity exercise and/or longer duration moderate intensity exercise than the current consensus recommendations suggest.

In other words, the current recommendations of 30 minutes of moderate intensity exercise 5 days per week probably won’t make much of a dent in your weight unless the exercise is coupled with a very good weight loss program.

But, if you have ever relied on exercise alone for weight loss, you have probably guessed that already!

Of course, the consensus recommendations are still valid for what they were designed to accomplish. 30 minutes a day of moderate intensity exercise 5 days per week is sufficient to improve fitness and reduce cardiovascular risk factors.  And fitness reduces your risk of disease even if you are still overweight.

Furthermore, since many Americans probably don’t get even 30 minutes of exercise in a week, 30 minutes 5 days per week is a great starting goal.

 

The Bottom Line 

Recent studies show that the current recommendations of 30 minutes of moderate intensity exercise 5 days per week probably won’t make much of a dent in your weight unless the exercise is coupled with a very good weight loss program.

Don’t freak out about all of the conflicting exercise recommendations. Here’s what I suggest:

1) Consult with your physician before you start any exercise program.

2) Get active. Start slowly and start by choosing activities that are fun and accessible to you.

3) Set your goal of 30 minutes of moderate intensity exercise 5 days per week. If you want to lose weight, couple that with a well-designed weight loss program.

4) If your combination of exercise and diet isn’t putting a dent in your weight and weight loss is important to you, pick up the pace or increase the duration of exercise.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Comments (2)

  • Helen T. Govedarica

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    Thank you for your wonderful info laden emails. They help me feel more knowledgeable when talking to my downline.

    Please note I have a new email address and am just making sure that you have changed your records.

    Thank You.

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    • Dr. Steve Chaney

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      Your records have been updated

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Latest Article

Can Plant-based Diets Be Unhealthy?

Posted September 10, 2019 by Dr. Steve Chaney

Do Plant-Based Diets Reduce Heart Disease Deaths?

Author: Dr. Stephen Chaney

 

plant-based diets vegetablesPlant-based diets have become the “Golden Boys” of the diet world. They are the diets most often recommended by knowledgeable health and nutrition professionals. I’m not talking about all the “Dr. Strangeloves” who pitch weird diets in books and the internet. I am talking legitimate experts who have spent their life studying the impact of nutrition on our health.

Certainly, there is an overwhelming body of evidence supporting the claim that plant-based diets are healthy. Going on a plant-based diet can help you lower blood pressure, inflammation, cholesterol and triglycerides. People who consume a plant-based diet for a lifetime weigh less and have decreased risk of heart disease, diabetes, and cancer.

But, can a plant-based diet be unhealthy? Some people consider a plant-based diet to simply be the absence of meat and other animal foods. Is just replacing animal foods with plant-based foods enough to make a diet healthy?

Maybe not. After all, sugar and white flour are plant-based food ingredients. Fake meats of all kinds abound in our grocery stores. Some are very wholesome, but others are little more than vegetarian junk food. If you replace animal foods with plant-based sweets, desserts, and junk food, is your diet really healthier?

While the answer to that question seems obvious, very few studies have asked that question. Most studies on the benefits of plant-based diets have compared population groups that eat a strictly plant-based diet (Seventh-Day Adventists, vegans, or vegetarians) with the general public. They have not looked at variations in plant food consumption within the general public. Nor have they compared people who consume healthy and unhealthy plant foods.

This study (H Kim et al, Journal of the American Heart Association, 8:e012865, 2019) was designed to fill that void.

 

How Was The Study Done?

plant-based diets studyThis study used data collected from 12,168 middle aged adults in the ARIC (Atherosclerosis Risk in Communities) study between 1987 and 2016.

The participant’s usual intake of foods and beverages was assessed by trained interviewers using a food frequency questionnaire at the time of entry into the study and again 6 years later.

Participants were asked to indicate the frequency with which they consumed 66 foods and beverages of a defined serving size in the previous year. Visual guides were provided to help participants estimate portion sizes.

The participant’s adherence to a plant-based diet was assessed using four different well-established plant-based diet scores. For the sake of simplicity, I will include 3 of them in this review.

  • The PDI (Plant-Based Diet Index) categorizes foods as either plant foods or animal foods. A high PDI score means that the participant’s diet contains more plant foods than animal foods. A low PDI score means the participant’s diet contains more animal foods than plant foods.
  • The hPDI (healthy plant-based diet index) is based on the PDI but emphasizes “healthy” plant foods. A high hPDI score means that the participant’s diet is high in healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) and low in animal foods.
  • The uPDI (unhealthy plant-based diet index) is based on the PDI but emphasizes “unhealthy” plant foods. A high uPDI score means that the participant’s diet is high in unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) and low in animal foods.

For statistical analysis the scores from the various plant-based diet indices were divided into 5 equal groups. In each case, the group with the highest score consumed the most plant foods and least animal foods. The group with the lowest score consumed the least plant foods and the most animal foods.

The health outcomes measured in this study were heart disease events, heart disease deaths, and all-cause deaths. Again, for the sake of simplicity, I will only include 2 of these outcomes (heart disease deaths and all-cause deaths) in this review. The data on deaths were obtained from state death records and the National Death Index. (Yes, your personal information is available on the web even after you die.)

 

Do Plant-Based Diets Reduce Heart Disease Deaths?

plant-based diets reduce heart deathsThe participants in this study were followed for an average of 25 years.

The investigators looked at heart disease deaths over the 25 years and compared people with the highest intake of plant foods to people with the highest intake of red meat and other animal foods. The results were:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, coffee and tea) had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods (refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts) had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

What Else Did The Study Show?

The investigators made a couple of other interesting observations:

  • The association of the overall diet with heart disease and all-cause deaths was stronger than the association of individual food components. This underscores the importance of looking at the effect of the whole diet on health outcomes rather than the “magic” foods you hear about on Dr. Strangelove’s Health Blog.
  • Diets with the highest amount of healthy plant foods were associated with higher intake of carbohydrates, plant protein, fiber, and micronutrients, including potassium, magnesium, iron, vitamin A, vitamin C, folate, and lower intake of saturated fat and cholesterol.
  • Diets with the highest amount of unhealthy plant foods were associated with higher intake of calories and carbohydrates and lower intake of fiber and micronutrients.

The last two observations may help explain some of the health benefits of plant-based diets.

 

Can Plant-Based Diets Be Unhealthy?

plant-based diets unhealthy cookiesNow, let’s return to the question I asked at the beginning of this article: “Can plant-based diets be unhealthy?” Although some previous studies have suggested that unhealthy plant-based diets might increase the risk of heart disease, this study did not show that.

What this study did show was that an unhealthy plant-based diet was no better for you than a diet containing lots of red meat and other animal foods.

If this were the only conclusion from this study, it might be considered a neutral result. However, this result clearly contrasts with the data from this study and many others showing that both plant-based diets in general and healthy plant-based diets reduce the risk of heart disease deaths and all-cause deaths compared to animal-based diets.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

There is one other subtle message from this study. This study did not compare vegans with the general public. Everyone in the study was the general public. Nobody in the study was consuming a 100% plant-based diet.

For example:

  • The group with the highest intake of plant foods consumed 9 servings per day of plant foods and 3.6 servings per day of animal foods.
  • The group with the lowest intake of plant foods consumed 5.4 servings per day of plant foods and 5.6 servings per day of animal foods.

In other words, you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet.

 

The Bottom Line

A recent study analyzed the effect of consuming plant foods on heart disease deaths and all-cause deaths over a 25-year period.

When the investigators looked at heart disease deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had a 19-32% lower risk of dying from heart disease than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

When the investigators looked at all-cause deaths over the 25 years:

  • People with the highest intake of plant foods and the highest intake of healthy plant foods had an 11-25% lower risk of dying from any cause than people with the highest intake of red meat and other animal foods.
  • People with the highest intake of unhealthy plant foods had the same risk of dying from heart disease as people with the highest intake of red meat and other animal foods.

The main message from this study is clear.

  • Replacing red meat and other animal foods with plant foods can be a healthier choice, but only if they are whole, minimally processed plant foods like whole grains, fruits, vegetables, nuts, legumes, coffee and tea.
  • If the plant foods are refined grains, fruit juices, French fries and chips, sugar sweetened and artificially sweetened beverages, sweets and desserts, all bets are off. You may be just as unhealthy as if you kept eating a diet high in red meat and other animal foods.

A more subtle message from the study is that you don’t need to be a vegan purist to experience health benefits from adding more whole, minimally processed plant foods to your diet. The people in this study were not following some special diet. The only difference was that some of the people in this study ate more plant foods and others more animal foods.

For more details on the study, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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