mortality Archives - Health Tips From The Professor

Are Low Carb Diets Healthier?

April 25, 2023 by Dr. Steve Chaney

The “Goldilocks Effect”

Author: Dr. Stephen Chaney

The low-carb wars rage on. Low-carb enthusiasts claim that low-carb diets are healthy. Many health experts warn about the dangers of low-carb diets. Several studies have reported that low-carb diets increase risk of mortality (shorten lifespan).

However, two recent studies have come to the opposite conclusion. Those studies reported that high carbohydrate intake increased mortality, and low carbohydrate intake was associated with the lowest mortality.

One of those studies, called the Prospective Urban Rural Epidemiology (PURE) study was published a few years ago. It included data from 135,335 participants from 18 countries across 5 continents. That’s a very large study, and normally we expect very large studies to be accurate. The results from the PURE study had low-carb enthusiasts doing a victory lap and claiming it was time to rewrite nutritional guidelines to favor low-carb diets.

Whenever controversies like this arise, reputable scientists are motivated to take another look at the question. They understand that all studies have their weaknesses and biases. So, they look at previous studies very carefully and try to design a study that eliminates the weaknesses and biases of those studies. Their goal is to design a stronger study that reconciles the differences between the previous studies.

A third study published a year later (SB Seidelmann et al, The Lancet, doi.org/10.1016/S2468-2667(18)30135-X was such a study. This study resolved the conflicting data and finally answered the question: “How much carbohydrate should we be eating if we desire a long and healthy life?” The answer is “Enough”.

I call this “The Goldilocks Effect”. You may remember “Goldilocks And The Three Bears”. One bed was too hard. One bed was too soft. But one bed was “just right”. One bowl of porridge was too hot. One was two cold. But one was “just right”. According to this study, the same is true for carbohydrate intake. High carbohydrate intake is unhealthy. Low carbohydrate intake is unhealthy. But moderate carbohydrate intake is “just right”.

How Was The Study Done?

This study was performed in two parts. This first part drew on data from the Atherosclerosis Risk in Communities (ARIC) study. That study enrolled 15,428 men and women, aged 45-64, from four US communities between 1987 and 1989. This group was followed for an average of 25 years, during which time 6283 people died. Carbohydrate intake was calculated based on food frequency questionnaires administered when participants enrolled in the study and again 6 years later. The study evaluated the association between carbohydrate intake and mortality.

The second part was a meta-analysis that combined the data from the ARIC study with all major clinical studies since 2007 that measured carbohydrate intake and mortality and lasted 5 years or more. The total number of participants included in this meta-analysis was 432,179, and it included data from previous studies that claimed low-carbohydrate intake was associated with decreased mortality.

Are Low Carb Diets Healthier?

The results from the ARIC study were:

The relationship between mortality and carbohydrate intake was a U-shaped curve.

- The lowest risk of death was observed with a moderate carbohydrate intake (50-55%). This is the intake recommended by current nutrition guidelines.

- The highest risk of death was observed with a low carbohydrate intake (<40%).

- The risk of death also increased with very high carbohydrate intake (>70%).

When the investigators used the mortality data to estimate life expectancy, they predicted a 50-year old participant would have a projected life expectancy of:

- 33.1 years if they had a moderate intake of carbohydrates.

- 4 years less if they had a low carbohydrate intake.

- 1.1 year less if they had a very high carbohydrate intake.

The risk associated with low carbohydrate intake was affected by what the carbohydrate was replaced with.

- When carbohydrates were replaced with animal protein and animal fat there was an increased risk of mortality on a low-carb diet. The animal-based low-carb diet contained more beef, pork, lamb, chicken, and fish. It was also higher in saturated fat.
- When carbohydrates were replaced with plant protein and plant fats, there was a decreased risk of mortality on a low-carb diet. The plant-based low-carb diet contained more nuts, peanut butter, dark or whole grain breads, chocolate, and white bread. It was also higher in polyunsaturated fats.

The effect of carbohydrate intake on mortality was virtually the same for all-cause mortality, cardiovascular mortality, and non-cardiovascular mortality.

There was no significant effect of carbohydrate intake on long-term weight gain (another myth busted).

The results from the dueling meta-analyses were actually very similar. When the data from all studies were combined:

Both very low carbohydrate diets and very high carbohydrate diets were associated with increased mortality.

Meat-based low-carb diets increased mortality, and plant-based low-carb diets decreased mortality.

Once again, the results were the same for total mortality, cardiovascular mortality, and non-cardiovascular mortality.

The authors concluded: “Our findings suggest a negative long-term association between life-expectancy and both low carbohydrate and high carbohydrate diets…These data also provide further evidence that animal-based low carbohydrate diets should be discouraged. Alternatively, when restricting carbohydrate intake, replacement of carbohydrates with predominantly plant-based fats and proteins could be considered as a long-term approach to healthy aging.”

Simply put, that means if a low carb diet works best for you, it is healthier to replace the carbs with plant-based fats and protein rather than animal-based fats and protein.

The “Goldilocks Effect”

This study also resolved the discrepancies between previous studies. The authors pointed out that the average carbohydrate intake is very different in Europe and the US than in Asian countries and low-income countries.

In the US and Europe mean carbohydrate intake is about 50% of calories and it ranges from 25% to 70% of calories. With that range of carbohydrate intake, it is possible to observe the increase in mortality associated with both very low and very high carbohydrate intakes.

The US and European countries are affluent, which means that low-carb enthusiasts can afford diets high in animal protein.

White rice is a staple in Asian countries, and protein is a garnish rather than a main course. Consequently, overall carbohydrate intake is greater in Asian countries and very few Asians eat a truly low carbohydrate diet. High protein foods tend to be more expensive than high carbohydrate foods. Thus, very few people in developing countries can afford to follow a very low carbohydrate diet, and overall carbohydrate intake also tends to be higher.

Therefore, in Asian and developing countries the average carbohydrate intake is greater (~61%) than in the US and Europe, and the range of carbohydrate intake is from 45% to 80% of calories. With that range of intake, it is only possible to see the increase in mortality associated with very high carbohydrate intake.

Both the studies that low-carb enthusiasts quote to support their claim that low-carb diets are healthy relied heavily on data from Asian and developing countries.

In fact, when the authors of the current study overlaid the data from the PURE study with their ARIC data, there was an almost perfect fit. The only difference was that their ARIC data covered both low and high carbohydrate intake while the PURE study touted by low-carb enthusiasts only covered moderate to high carbohydrate intake.

[I have given you my rendition of the graph on the right. If you would like to see the data yourself, look at the paper.]

Basically, low-carb advocates are telling you that diets with carbohydrate intakes of 30% or less are healthy based on studies that did not include carbohydrate intakes below 40%. That is misleading. The studies they quote are incapable of detecting the risks of low carbohydrate diets.

What Does This Study Mean For You?

There are several important take-home lessons from this study:

All major studies agree that very high carbohydrate intake is unhealthy. In part, that reflects the fact that diets with high carbohydrate intake are likely to be high in sodas and sugary junk foods. It may also reflect the fact that diets which are high in carbohydrate are often low in plant protein or healthy fats or both.

All studies that cover the full range of carbohydrate intake agree that very low carbohydrate intake is also unhealthy. It shortens the life expectancy of a 50-year-old by about 4 years.

The studies quoted by low carb enthusiasts to support their claim that low-carb diets are healthy don’t include carbohydrate intakes below 40%. That means their claims are misleading. The studies they quote are incapable of detecting the risks of low carbohydrate diets.

Meat-based low-carb diets decrease life expectancy while plant-based low carb diets increase life expectancy. This is consistent with previous studies. For more details on those studies, see my article, “Are Any Low-Carb Diets Healthy?”, in “Health Tips From The Professor” or my book, “Slaying The Food Myths”.

The health risks of meat-based low-carb diets may be due to the saturated fat content or the heavy reliance on red meat. However, the risks are just as likely to be due to the foods these diets leave out – typically fruits, whole grains, legumes, and some vegetables.

Proponents of low-carb diets assume that you can make up for the missing nutrients by just taking multivitamins. However, each food group also provides a unique combination of phytonutrients and fibers. The fibers, in turn, influence your microbiome. Simply put, whenever you leave out whole food groups, you put your health at risk.

The Bottom Line

The low-carb wars are raging. Several studies have reported that low-carb diets increase risk of mortality (shorten lifespan). However, two studies published a few years ago have come to the opposite conclusion. Those studies have low-carb enthusiasts doing a victory lap and claiming it is time to rewrite nutritional guidelines to favor low-carb diets.

However, a study published a year later resolves the conflicting data and finally answers the question: “How much carbohydrate should we be eating if we desire a long and healthy life?” The answer is “Enough”.

I call this “The Goldilocks Effect”. According to this study, high carbohydrate intake is unhealthy. Low carbohydrate intake is unhealthy. But, moderate carbohydrate intake is “just right”.

Specifically, this study reported:

Moderate carbohydrate intake (50-55%) is healthiest. This is also the carbohydrate intake recommended by current nutritional guidelines.

2) All major studies agree that very high carbohydrate intake (60-70%) is unhealthy. It shortens life expectancy of a 50-year old by about a year.

3) All studies that cover the full range of carbohydrate intake agree that low carbohydrate intake (<40%) is also unhealthy. It shortens life expectancy of a 50-year old by about 4 years.

4) The studies quoted by low carb enthusiasts to support their claim that low-carb diets are healthy don’t include carbohydrate intakes below 40%. That means their claims are misleading. The studies they quote are incapable of detecting the risks of low carbohydrate diets.

5) Meat-based low-carb diets decrease life expectancy while plant-based low carb diets increase life expectancy. This is consistent with the results of previous studies.

Simply put, that means if a low carb diet works best for you, it is healthier to replace the carbs with plant-based fats and protein rather than animal-based fats and protein.

For more details, 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.

Walking Your Way To Health

December 27, 2022 by Dr. Steve Chaney

How Much Should You Walk?

Author: Dr. Stephen Chaney

The new year is almost here. If you are like millions of Americans, you may already be making plans to join a gym, get a personal trainer, or join a spin class.

The problem is these are all expensive options. And a good portion of that money is wasted. To put it into perspective, let’s look at some statistics

Around 6 million Americans buy gym memberships every January.

67% of those memberships are never used.

For those memberships used in January, another 50% are not in use 6 months later.

Americans spend about 1.6 billion dollars on unused gym memberships every year.

And that doesn’t include those gym memberships that are only occasionally used.

If you want to get fit and healthy in the new year, perhaps you should consider a less expensive option – like walking. Your only investments are a good pair of walking shoes and a device that keeps track of the number of steps you take (eg, Fitbit, smart watch, or smart phone).

You still may give up on your New Year’s goal of getting fitter at some point. But you won’t have wasted so much money.

Of course, you probably have some questions about the benefits of walking, such as:

Is walking enough to significantly improve my fitness and health?

2) How far (how many steps) should I walk?

3) How fast should I walk?

Fortunately, two recent studies (B del Pozo-Cruz et al, JAMA Internal Medicine, 182: 1139-1148, 2022; J del Pozo-Cruz et al, Diabetes Care, 45: 2156-2158, 2022) have answered all three questions.

How Were These Studies Done?

The first study (B del Pozo-Cruz et al, JAMA Internal Medicine, 182: 1139-1148, 2022) followed 78,500 participants (average age 61, 55% female, 97% white) enrolled in the UK Biobank study for an average of 7 years.

At the time of enrollment, each participant was given an accelerometer (a device that measures the number and frequency of steps) to wear on their dominant wrist for 24 hours/day for 7 days. The investigators used the accelerometer data to categorize several types of physical activity.

Daily step counts (the average number of steps per day for 7 days). These step counts were further subdivided into two categories:

Incidental steps (It was assumed that ˂40 steps/min represented steps taken that were incidental to normal daily activities).

Purposeful steps (It was assumed that ≥40 steps/min represented steps taken as part of planned exercise).

Stepping intensity (the highest frequency of steps/min averaged over 30 min intervals for all 7 days).

At the end of the study, each of these variables was correlated with the risk of premature deaths due to all causes, cancer, and heart disease.

The second study (J del Pozo-Cruz et al, Diabetes Care, 45: 2156-2158, 2022) was similar except that it:

Used data from 1687 adults (average age = 55, 56% male, with diabetes or prediabetes when the study began) in the 2005-2006 National Health and Nutrition Examination Survey in the US.

Followed participants for 9 years instead of 7.

Only measured total steps/day

Correlated total steps/day with premature death for participants who already had prediabetes or diabetes when they entered the study.

Walking Your Way To Health

Study 1 looked at the effect of walking on health outcomes in multiple ways.

#1: Increase in number of steps/day:

On average study participants took an average of 7200 steps per day, but this ranged from a low of 3,200 steps/day to a high of 12,200 steps/day.

Each increase of 2,000 steps/day was associated with a:

- 8% decrease in all-cause mortality.

- 11% decrease in cancer mortality.

- 10% decrease in heart disease mortality.

Overall, increasing from 3,200 steps/day to 10,000 steps/day decreased all-cause, cancer, and heart disease mortality by around 36%.

There was no minimum threshold to this beneficial effect of walking on the risk of premature death.

The benefits of walking appeared to plateau at 10,000 steps/day.

#2: Increase in number of incidental steps/day (steps taken that are incidental to normal daily activities):

On average study participants took 3240 incidental steps/day, but this ranged from a low of 2,100 steps/day to a high of 4,400 steps/day.

Each 10% increase in incremental steps/day was associated with a:

- 6% decrease in all-cause mortality.

- 6% decrease in cancer mortality.

- 10% decrease in heart disease mortality.

#3: Increase in number of purposeful steps/day (steps taken as part of planned exercise):

On average study participants took 4,600 purposeful steps/day, but this ranged from a low of 1,600 steps/day to a high of 8,600 steps/day.

Each 10% increase in purposeful steps/day was associated with a:

- 7% decrease in all-cause mortality.

- 8% decrease in cancer mortality.

- 10% decrease in heart disease mortality.

#4: Increase in speed of walking or cadence. The measurement they used was “peak-30 cadence” – the highest average steps/min during a 30-minute interval within a day:

On average study participants had a “peak-30 cadence” of 76 steps/min, but this ranged from a low of 47 steps/min to a high of 109 steps/min.

Each 10% increase in “peak-30 cadence” was associated with a:

- 8% decrease in all-cause mortality.

- 9% decrease in cancer mortality.

- 14% decrease in heart disease mortality.

The benefits of walking rapidly (increase in “peak-30 cadence”) were in addition to the benefits seen by increasing the number of steps per day.

Overall, increasing from a “peak-30 cadence” of 47 steps/min to 109 steps/min decreased all-cause, cancer, and heart disease mortality by an additional 34%.

There was no minimum threshold to this beneficial effect of increasing “peak-30 cadence” (the speed of walking) on the risk of premature death.

The benefits of increasing “peak-30 cadence” appeared to plateau at 100 steps/min.

#5 Effect of walking on the prevention of heart disease and cancer: The investigators measured this by looking at the effect of walking on the “incidence” of heart disease and cancer (defined as new diagnoses of heart disease and cancer) during the study. They found.

Each 2,000-step increase in the total number of steps/day decreased the risk of developing heart disease and cancer by 4% during this 7-year study.

Each 10% increase in the number of purposeful steps/day decreased the risk of developing heart disease and cancer by 4% during this study.

Each 10% increase in “peak-30 cadence” decreased the risk of developing heart disease and cancer by 7% during this study.

The authors concluded, “The findings of this population-based…study of 78,500 individuals suggest that up to 10,000 steps/day may be associated with a lower risk of mortality and cancer and CVD incidence. Steps performed at a higher cadence may be associated with additional risk reduction, particularly for incident disease.”

Study 2 extended these findings to diabetes. They started with participants that had either prediabetes or diabetes and followed them for 9 years. They found that:

Study participants with prediabetes ranged from a low of 3,800 steps/day to a high of 10,700 steps/day.

- Prediabetic participants walking 10,700 steps/day were 25% less likely to die during the study than participants walking only 3,800 steps/day.

Study participants with diabetes ranged from a low of 2,500 steps/day to a high of 10,200 steps/day.

- Diabetic participants walking 10,200 steps/day were also 25% less likely to die during the study than participants walking only 2,500 steps/day.

Even small increases in the number of steps per day decreased the risk of premature death for both prediabetic and diabetic participants.

Once again, 10,000 steps/day appeared to be the optimal dose to lower the risk of premature death for both diabetic and prediabetic patients.

The authors of this study concluded, “Accumulating more steps/day up to ~10,000 steps/day may lower the risk of all-cause mortality of adults with prediabetes and diabetes.”

How Much Should You Walk?

That was a lot of information. You are probably wondering what it means for you. Let’s start with the big picture:

Going from couch potato to 10,000 steps per day may reduce your risk of premature death due to all causes, cancer, and heart disease by 36% (24% if you are already prediabetic or diabetic).

Increasing the speed with which you walk from 47 steps/min to 109 steps/min sustained for 30 minutes may reduce your risk of premature death by an additional 34%.

In other words, simply walking more and walking faster can have a significant on your health. I am not recommending walking as your only form of exercise. I’m just saying not to consider it inferior to other forms of exercise.

There is no lower limit to the benefits of walking. Even small increases in the number of steps/day you take and the speed with which you walk may have a beneficial effect on your health.

In other words, you don’t need to speed walk 10,000 steps/day to reap a benefit from walking. Even small increases are beneficial. That’s good news for those of you who may not be able to speed walk long distances. It also means that if you are a couch potato, you don’t need to attempt 10,000 steps at high speed from day 1. You can work up to it gradually.

Incidental walking (walking that is incidental to your daily activities) is almost as beneficial as purposeful walking (walking as part of a planned exercise).

That’s good news for those of you who may not have time for long walks. It also means that advice like “park your car at the far end of the parking lot and walk” or “take the stairs rather than the elevator” can have a meaningful impact on your health.

The benefits of walking appear to max out at around 10,000 steps per day and a cadence of 100 steps/min sustained for 30 minutes.

That means once you get to those levels, it’s time to consider adding other kinds of exercise to your regimen. More and faster walking may offer little additional benefit.

Finally, in the words of the authors, “This information could be used to motivate the least active individuals to increase their steps and the more-active individuals to reach the 10,000-step target.”

The Bottom Line

The new year is almost here. If you are like millions of Americans, you may already be making plans to join a gym, get a personal trainer, or join a spin class.

If you want to get fit and healthy in the new year, perhaps you should also consider a less expensive option – like walking.

Of course, you probably have some questions about the benefits of walking, such as:

1) Is walking enough to significantly improve my fitness and health?

2) How far (how many steps) should I walk?

3) How fast should I walk?

Fortunately, two recent studies have answered all three questions. They found:

Going from couch potato to 10,000 steps per day may reduce your risk of premature death due to all causes, cancer, and heart disease by 36% (24% if you are already prediabetic or diabetic).

Increasing the speed with which you walk from 47 steps/min to 109 steps/min sustained for 30 minutes may reduce your risk of premature death by an additional 34%.

There is no lower limit to the benefits of walking. Even small increases in the number of steps/day you take and the speed with which you walk may have a beneficial effect on your health.

Incidental walking (walking that is incidental to your daily activities) is almost as beneficial as purposeful walking (walking as part of a planned exercise).

The benefits of walking appear to max out at around 10,000 steps per day and a cadence of 100 steps/min sustained for 30 minutes.

In the words of the authors of these studies, “This information could be used to motivate the least active individuals to increase their steps and the more-active individuals to reach the 10,000-step target.”

For more details on this study and what it means for you, 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.

Should I Avoid Whole Grains?

July 14, 2020 by Dr. Steve Chaney

Will Whole Grains Kill Me?

It seems like just yesterday that health experts all agreed that whole grains were good for us. After all:

They are a good source of fiber, B vitamins, vitamin E, and the minerals magnesium, iron, zinc, manganese, and selenium.

Their fiber fills you up, so you are less likely to overeat. This helps with weight control.

Their fiber also supports the growth of friendly bacteria in your gut.

In fact, the USDA still recommends that half of the grains we eat should be whole grains. And, outside experts, not influenced by the food industry, feel this recommendation is too low. They feel most of the grains we eat should be whole grains. Foods made from refined grains should be considered as only occasional treats.

Then the low-carb craze came along. Diets like Paleo and Keto were telling you to avoid all grains, even whole grains. Even worse, Dr. Strangelove and his colleagues were telling you whole grains contained something called lectins that were bad for you. Suddenly, whole grains went from being heroes to being villains.

You are probably asking, “Should I avoid whole grains?” What is the truth? Perhaps the best way to resolve this debate is to ask, how healthy are people who consume whole grains for many years? This week I share a recent study (G Zong et al, Circulation, 133: 2370-2380, 2016) that answers that very question.

How Was The Study Done?

This study was a meta-analysis of 14 clinical trials that:

Enrolled a total of 786,076 participants.

Obtained a detailed diet history at baseline.

Followed the participants for an average of 15 years (range = 6-28 years).

Determined the effect of whole grain consumption on the risk of death from heart disease, cancer, and all causes.

Will Whole Grains Kill Me?

Dr. Strangelove and his colleagues are claiming that whole grains cause inflammation, which increases your risk of heart disease and cancer. Heart disease and cancer are the leading causes of death in this country. In fact, according to the CDC, heart disease and cancer accounted for 44% of all deaths in the US in 2017.

Therefore, if Dr. Strangelove and his colleagues were correct, consumption of whole grains should increase the risk of deaths due to heart disease and cancer – and increase the risk of death due to all causes.

That is not what this study showed.

When the highest whole grain intake (5 servings/day) was compared with the lowest whole grain intake (0 servings/day), whole grain consumption reduced the risk of death from:

Heart disease by 18%.

Cancer by 12%.

All causes by 16%.

Furthermore, the effect of whole grains on mortality showed an inverse dose response. Simply put, the more whole grains people consumed, the lower the risk of deaths from heart disease, cancer, and all causes.

However, the dose response was not linear. Simply going from 0 servings of whole grains to one serving of whole grains reduced the risk of death from.

Heart disease by 9%.

Cancer by 5%.

All causes by 7%.

The authors concluded: “Whole grain consumption was inversely associated with mortality in a dose-response manner, and the association with cardiovascular mortality was particularly strong and robust. These observations endorse current dietary guidelines that recommend increasing whole grain intake to replace refined grains to facilitate long-term health and to help prevent premature death.”

The authors went on to say: “Low-carbohydrate diets that ignore the health benefits of whole grain foods should be adopted with caution because they have been linked to higher cardiovascular risk and mortality.”

Should I Avoid Whole Grains?

As for the original question, “Should I avoid whole grains?”, the answer appears to be a clear, “No”.

The strengths of this study include the large number of participants (786,076) and the demonstration of a clear dose-response relationship between whole grain intake and reduced mortality.

This study is also consistent with several other studies that show whole grain consumption is associated with a lower risk of heart disease, diabetes, cancer – and appears to lead to a longer, healthier life.

In short, it appears that Dr. Strangelove and the low-carb enthusiasts are wrong. Whole grains aren’t something to avoid. They reduce the risk of heart disease, diabetes, and cancer. And they reduce the risk of premature death. We should be eating more whole grains, not less.

However, the authors did point out that this study has some weaknesses:

It is an association study, which does not prove cause and effect.

Study participants who consumed more whole grains also tended to consume more fruits and vegetables – and less red meat, sodas, and highly processed foods.

However, I would argue the second point is a strength, not a weakness. We need to give up the idea that certain foods or food groups are “heroes” or “villains”. We know that primarily plant-based diets like the Mediterranean and DASH diets are incredibly healthy. Does it really matter how much of those health benefits come from whole grains and how much comes from fruits and vegetables?

The Bottom Line

Dr. Strangelove and low-carb enthusiasts have been telling us we should avoid all grains, including whole grains. Is that good advice?

If Dr. Strangelove and his colleagues were correct, consumption of whole grains should increase the risk of deaths due to the top two killer diseases, heart disease and cancer. Furthermore, because heart disease and cancer account for 44% of all deaths in this country, whole grain consumption should also increase the risk of death due to all causes.

A recent study showed the exact opposite. The study showed:

When the highest whole grain intake (5 servings/day) was compared with the lowest whole grain intake (0 servings/day), whole grain consumption reduced the risk of death from:

Heart disease by 18%.

Cancer by 12%.

All causes by 16%.

However, the dose response was not linear. Simply going from 0 servings of whole grains to one serving of whole grains reduced the risk of death from.

Heart disease by 9%.

Cancer by 5%.

All causes by 7%.

For more details 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.