Math, Obesity & You: Is a Calorie Still a Calorie?
Posted: Tue Apr 21, 2015 7:40 am
I just posted the following as comments in the Lounge and thought I would repost it here. I wrote most of it a while ago in a discussion with my colleagues when the new equation first came out. Here is the link to the discussion in the Lounge
viewtopic.php?f=1&t=47820
Math, Obesity & You: Is a Calorie Still a Calorie?
Jeff Novick, MS, RDN
A few years ago, Kevin Hall proposed a new mathematical model of calories and weight loss to help predict weight loss more accurately. The headlines that followed claimed that the 3500 calorie rule (you have to burn 3500 calories to lose a pound of fat) was wrong and and that a calorie is not a calorie.
The work on this topic is excellent and, for those interested, a well deserved read.
Here are a few related articles (some of which are in my BMI thread) by Kevin Hall..
Energy balance and its components: implications for body weight regulation1
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3302369/
Quantification of the effect of energy imbalance on bodyweight
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3880593/
Short and long-term energy intake patterns and their implications for human body weight regulation
http://www.sciencedirect.com/science/ar ... 8414001140
This is the article in the Lancet that challenged the old equation.
http://www.thelancet.com/journals/lance ... X/abstract
This is a WSJ article on the above published article. Not sure if it is public or you need a log in.
http://online.wsj.com/article/SB2000142 ... 10584.html
This is the new weight loss simulator from the NIH that is supposed to be more accurate
http://bwsimulator.niddk.nih.gov/
For the record, the lancet article came out with a new formula and calculator which is still a "rule of thumb" and is only trying to better account for and calculate some of the issues discussed.
This is an interview in the NY Times a few years back with Carson Chow, PhD, a colleague of Kevin Hall's...
http://www.nytimes.com/2012/05/15/scien ... ref=health
As pointed out, the actual title of the thread in the Lounge, "3500 calories less =1 pound weight loss myth now debunked," is not the main point of the article.
He argues that a calorie is a calorie but that many equations have not taken into account adaptions the body makes during the process of weight loss, one being as simple as that as we lose weight there is less of us, so our metabolic rate goes down accordingly and we burn less calories.
There are some variables that impact the equation that we know & can account for. However, there some we either don't know or that we can’t measure very well and therefore, cannot account for them.
This is the point I make, though in much simpler terms, in these articles...
How To Successfully Count Calories
http://www.jeffnovick.com/RD/Articles/E ... ories.html
Do You Know How Many Calories Are In The Food You Eat
http://www.jeffnovick.com/RD/Articles/E ... u_Eat.html
And this recent discussion on losing weight and is food really unlimited
viewtopic.php?f=22&t=27333&p=272969#p272671
He even concludes "You simply have to cut calories and be vigilant for the rest of your life."
And that the problem is simple a matter of excess calories.
"The price of food plummeted, while the number of calories available to the average American grew by about 1,000 a day. Well, what do people do when there is extra food around? They eat it! This, of course, is a tremendously controversial idea. However, the model shows that increase in food more than explains the increase in weight."
So, a calorie is still a calorie, and the 3500 calorie "rule of thumb" (which I will address below) still works, but the equations trying to explain calorie math, were wrong.
The following is from a personal conversation with Kevin Hall...
"In the Consensus Statement paper where it says it takes 3 years to achieve 95% weight loss, that is specifically for when 500 calories is lobbed off starting-weight-energy-needs and never adjusted any further. If you maintain a 500-calorie deficit however (which requires ratcheting your EI down along with weight loss), weight loss follows the 1st law of thermodynamics as expected."
In regard to the rule of thumb, "you have to burn 3500 calories to lose 1 lb"....
There are many rules of thumb that are used in medicine, nutrition and fitness that, while they may just be rules of thumb and not perfect, they do not invalidate the science (or laws) they are based on. It is the same with all the markers, risk factors and screening tools we use from BMI, cholesterol, waist circumference, etc.
For instance, we say, walking or running a mile burns the same calories, which is about 100 calories. Some nutritionists use body weight x 10 for an estimate of RMR. Both of these 2 examples have been used for a very long time. However, neither of them are accurate if you actually measure them. It does not invalidate the principles they are based on. They are just a simplified way of estimating these issues.
The numbers we use for the caloric value of protein, carb and fat, The Atwater Values, of 4/4/9 (calories per gram), are also rules of thumb. This does not invalidate the science and principle they are based on.
In addition, there are about 4 different ways the FDA allows the industry to calculate them so even similar products can have different values on their labels. Knowing this helps to understand why the "rule of thumb" of 4/4/9 does not always work out perfectly and why some differences exist.
Accuracy In Nutrition: How Accurate Are The Atwater Values
http://www.jeffnovick.com/RD/Q_%26_As/E ... alues.html
The 3500 was also a rule of thumb and there are very good reasons why it does not work 100% when applied to real people, but that in no way invalidates the science and the physics behind it. .
Where did the rule come from?
They say 1 gram of fat is 9 calories. However, as I showed in my linked article on where these numbers come from, this is also just a “rule of thumb” and not very accurate so we have an issue right there. It may range from 7-10. Second, a pound is 454 grams which, x 9 is 4086 calories, not 3500. So where did 3500 come from?
If you reverse the math, and divide the 3500 by 454, you get 7.7 calories per gram. So, where did they get the 7.7 or the 3500?
The difference is the fact that fat tissue is not 100% pure fat. It also has varying amounts of protein and water, which also varies depending on the type of fat and where it may be located.
So, based on the 3500 calories being the number commonly used for a pound of fat tissue and based on 9 calories per gram, we can say fat tissue is about 85% fat. (as a rule of thumb)
(It is actually less and some of the remaining tissue is protein which yields a few calories too. So it is more like 75-80% fat and a few percentages of protein and a few of water). But for simplicity sake, lets use 85%.
However, as we all know, people are different and some lose weight quickly and seemingly effortlessly and others experience very slow and laborious weight loss.
And we are learning more and more as time goes on, some of which we can measure and add to the equation. For instance, one factor in regard to energies out that has come to light is NEAT (non exercise activity thermogenesis) which was never accounted for in the old energy balance equation and can have an impact of 300-400 calories day.
We also all know that there are confounding factors including actual intake vs. assumed intake, body composition factors and activity level, etc. etc. etc.
Let’s say muscle tissue is about 30% protein and fat tissue is about 85% fat (see above).
There is an assumption that 100% fat is being lost for each pound of weight lost but as we all know, it’s not true.
So, lets just look at two extremes.
If the weight lost was 100% fat tissue, that would provide the 3500 calories (454 gm x .85 (85% fat) = 385.9 x 9 (calories per gram) = 3473 (which is rounded up to 3500). Now we see where the 3500 came from.
However, if the weight loss was 100% muscle tissue, that would provide about 600 calories. (454 gm x .3 (30% protein) = 136.2 x 4 (calories per gram) = 544 calories, and lets round up to 550.
Knowing this, we can easily see how two people could lose different amounts of weight on the same calorie deficit depending on what percentage of fat or muscle the loss came from.
If you had an energy deficit of 3500 calories and it came 100% from fat tissue, it would be 1 lb of weight lost. However, if the 3500 calories came from 100% muscle tissue, it would be 6.36 lbs of wt lost. And, if the 3500 calories came from 50% fat and 50% muscle, the weight loss would be 3.68 lbs.
So the varying amounts of weight loss, from 1 to 6.36 pounds, do not in any way invalidate the formula or the science.
And, it turns out that the amount of fat and/or muscle you lose during weight loss (or gain) is influenced by your starting body composition.
viewtopic.php?f=22&t=8079&p=58408#p58408
The new equation is fascinating as is the work it is based on. That is how science works. However, I doubt it will have any impact on the obesity epidemic or any individuals efforts to lose weight. It is still a "rule of thumb," not 100% accurate and only trying to better account for and calculate some of the things discussed.
This is where calorie density shines.
The principles of calorie density are so much easier for anyone to understand, to apply and to adjust as needed to manage their weight.
In Health
Jeff
viewtopic.php?f=1&t=47820
Math, Obesity & You: Is a Calorie Still a Calorie?
Jeff Novick, MS, RDN
A few years ago, Kevin Hall proposed a new mathematical model of calories and weight loss to help predict weight loss more accurately. The headlines that followed claimed that the 3500 calorie rule (you have to burn 3500 calories to lose a pound of fat) was wrong and and that a calorie is not a calorie.
The work on this topic is excellent and, for those interested, a well deserved read.
Here are a few related articles (some of which are in my BMI thread) by Kevin Hall..
Energy balance and its components: implications for body weight regulation1
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3302369/
Quantification of the effect of energy imbalance on bodyweight
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3880593/
Short and long-term energy intake patterns and their implications for human body weight regulation
http://www.sciencedirect.com/science/ar ... 8414001140
This is the article in the Lancet that challenged the old equation.
http://www.thelancet.com/journals/lance ... X/abstract
This is a WSJ article on the above published article. Not sure if it is public or you need a log in.
http://online.wsj.com/article/SB2000142 ... 10584.html
This is the new weight loss simulator from the NIH that is supposed to be more accurate
http://bwsimulator.niddk.nih.gov/
For the record, the lancet article came out with a new formula and calculator which is still a "rule of thumb" and is only trying to better account for and calculate some of the issues discussed.
This is an interview in the NY Times a few years back with Carson Chow, PhD, a colleague of Kevin Hall's...
http://www.nytimes.com/2012/05/15/scien ... ref=health
As pointed out, the actual title of the thread in the Lounge, "3500 calories less =1 pound weight loss myth now debunked," is not the main point of the article.
He argues that a calorie is a calorie but that many equations have not taken into account adaptions the body makes during the process of weight loss, one being as simple as that as we lose weight there is less of us, so our metabolic rate goes down accordingly and we burn less calories.
There are some variables that impact the equation that we know & can account for. However, there some we either don't know or that we can’t measure very well and therefore, cannot account for them.
This is the point I make, though in much simpler terms, in these articles...
How To Successfully Count Calories
http://www.jeffnovick.com/RD/Articles/E ... ories.html
Do You Know How Many Calories Are In The Food You Eat
http://www.jeffnovick.com/RD/Articles/E ... u_Eat.html
And this recent discussion on losing weight and is food really unlimited
viewtopic.php?f=22&t=27333&p=272969#p272671
He even concludes "You simply have to cut calories and be vigilant for the rest of your life."
And that the problem is simple a matter of excess calories.
"The price of food plummeted, while the number of calories available to the average American grew by about 1,000 a day. Well, what do people do when there is extra food around? They eat it! This, of course, is a tremendously controversial idea. However, the model shows that increase in food more than explains the increase in weight."
So, a calorie is still a calorie, and the 3500 calorie "rule of thumb" (which I will address below) still works, but the equations trying to explain calorie math, were wrong.
The following is from a personal conversation with Kevin Hall...
"In the Consensus Statement paper where it says it takes 3 years to achieve 95% weight loss, that is specifically for when 500 calories is lobbed off starting-weight-energy-needs and never adjusted any further. If you maintain a 500-calorie deficit however (which requires ratcheting your EI down along with weight loss), weight loss follows the 1st law of thermodynamics as expected."
In regard to the rule of thumb, "you have to burn 3500 calories to lose 1 lb"....
There are many rules of thumb that are used in medicine, nutrition and fitness that, while they may just be rules of thumb and not perfect, they do not invalidate the science (or laws) they are based on. It is the same with all the markers, risk factors and screening tools we use from BMI, cholesterol, waist circumference, etc.
For instance, we say, walking or running a mile burns the same calories, which is about 100 calories. Some nutritionists use body weight x 10 for an estimate of RMR. Both of these 2 examples have been used for a very long time. However, neither of them are accurate if you actually measure them. It does not invalidate the principles they are based on. They are just a simplified way of estimating these issues.
The numbers we use for the caloric value of protein, carb and fat, The Atwater Values, of 4/4/9 (calories per gram), are also rules of thumb. This does not invalidate the science and principle they are based on.
In addition, there are about 4 different ways the FDA allows the industry to calculate them so even similar products can have different values on their labels. Knowing this helps to understand why the "rule of thumb" of 4/4/9 does not always work out perfectly and why some differences exist.
Accuracy In Nutrition: How Accurate Are The Atwater Values
http://www.jeffnovick.com/RD/Q_%26_As/E ... alues.html
The 3500 was also a rule of thumb and there are very good reasons why it does not work 100% when applied to real people, but that in no way invalidates the science and the physics behind it. .
Where did the rule come from?
They say 1 gram of fat is 9 calories. However, as I showed in my linked article on where these numbers come from, this is also just a “rule of thumb” and not very accurate so we have an issue right there. It may range from 7-10. Second, a pound is 454 grams which, x 9 is 4086 calories, not 3500. So where did 3500 come from?
If you reverse the math, and divide the 3500 by 454, you get 7.7 calories per gram. So, where did they get the 7.7 or the 3500?
The difference is the fact that fat tissue is not 100% pure fat. It also has varying amounts of protein and water, which also varies depending on the type of fat and where it may be located.
So, based on the 3500 calories being the number commonly used for a pound of fat tissue and based on 9 calories per gram, we can say fat tissue is about 85% fat. (as a rule of thumb)
(It is actually less and some of the remaining tissue is protein which yields a few calories too. So it is more like 75-80% fat and a few percentages of protein and a few of water). But for simplicity sake, lets use 85%.
However, as we all know, people are different and some lose weight quickly and seemingly effortlessly and others experience very slow and laborious weight loss.
And we are learning more and more as time goes on, some of which we can measure and add to the equation. For instance, one factor in regard to energies out that has come to light is NEAT (non exercise activity thermogenesis) which was never accounted for in the old energy balance equation and can have an impact of 300-400 calories day.
We also all know that there are confounding factors including actual intake vs. assumed intake, body composition factors and activity level, etc. etc. etc.
Let’s say muscle tissue is about 30% protein and fat tissue is about 85% fat (see above).
There is an assumption that 100% fat is being lost for each pound of weight lost but as we all know, it’s not true.
So, lets just look at two extremes.
If the weight lost was 100% fat tissue, that would provide the 3500 calories (454 gm x .85 (85% fat) = 385.9 x 9 (calories per gram) = 3473 (which is rounded up to 3500). Now we see where the 3500 came from.
However, if the weight loss was 100% muscle tissue, that would provide about 600 calories. (454 gm x .3 (30% protein) = 136.2 x 4 (calories per gram) = 544 calories, and lets round up to 550.
Knowing this, we can easily see how two people could lose different amounts of weight on the same calorie deficit depending on what percentage of fat or muscle the loss came from.
If you had an energy deficit of 3500 calories and it came 100% from fat tissue, it would be 1 lb of weight lost. However, if the 3500 calories came from 100% muscle tissue, it would be 6.36 lbs of wt lost. And, if the 3500 calories came from 50% fat and 50% muscle, the weight loss would be 3.68 lbs.
So the varying amounts of weight loss, from 1 to 6.36 pounds, do not in any way invalidate the formula or the science.
And, it turns out that the amount of fat and/or muscle you lose during weight loss (or gain) is influenced by your starting body composition.
viewtopic.php?f=22&t=8079&p=58408#p58408
The new equation is fascinating as is the work it is based on. That is how science works. However, I doubt it will have any impact on the obesity epidemic or any individuals efforts to lose weight. It is still a "rule of thumb," not 100% accurate and only trying to better account for and calculate some of the things discussed.
This is where calorie density shines.
The principles of calorie density are so much easier for anyone to understand, to apply and to adjust as needed to manage their weight.
In Health
Jeff