Is it ok to have a high BMI if it’s due to muscle?

Posted on May 9, 2014

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One of the things I’ve long been skeptical of is the assailment of BMI. If you’re unfamiliar:

  • Body Mass Index (BMI) is a simple, quick way to try and determine someone’s metabolic health.
  • It uses two variables, your mass and height.

BMI equation

From Wikipedia.

From Wikipedia.

  • Because the equation uses only your mass and height, it’s not telling you a whole lot about a person’s function, the type of weight they have on them (e.g. muscle versus fat), not to mention all the other aspects that go with health.

This “type of weight” aspect is where the fitness world gets all bent out of shape. The problem, to them at least, is because the equation doesn’t differentiate between muscle and fat, too many people who have a good deal of muscle on their frame are still equated -BMI wise- with being overweight or obese.

Take your average height male, 1.78 meters (5 feet 10 inches). Let’s say he’s 91 kilograms (200 pounds). BMI 200 pounds 5 feet 10 According to the BMI scale, this person is flirting with obesity. Where the fitness world will chime in is, “But we don’t know if that 200 pounds is with 10% body fat or 30%. If this person lifts weights that 200 pounds could be from having extra muscle on their frame, which is perfectly fine.” In fact, many in the fitness arena seek this profile.

As someone who has had a high BMI but low body fat, I never felt “healthy” during that time. Having that much muscle on my frame was work. It was a lot of intense resistance training, it was a lot of calories to take in, and I had to be aware I wasn’t burning many calories either. Beyond that, part of me has always felt at some point, weight is weight. Is it better to have it as muscle? Yes. Once you get beyond a certain point is it unhealthy regardless? I’ve always had an inkling it might be.

Enter “healthy obesity”

I don’t think it’s hard to grasp there’s not much research on the above group. In terms of getting an adequate sample size, there’s not many obese but jacked people walking around. From a research perspective, this isn’t exactly a pressing issue either. I think we can look at this in a slightly indirect manner though.

Healthy obesity is the idea despite having a high BMI, a person may still have a good metabolic profile. You know, healthy blood pressure, cholesterol, glucose levels, your typical blood work at the doctor visit. Where even though the person’s overweight or obese, they seem to be doing alright.

Researchers have wanted to know if, despite having healthy blood work, these people were still less healthy than someone with a “normal” BMI and healthy blood work. You and I are both healthy metabolically, I’m at a normal BMI but you’re at an obese level, should you be concerned?

Most recently (April 2014) a study which looked at 14,828 Korean adults found:

“Metabolically healthy obese (MHO) participants had a higher prevalence of subclinical coronary atherosclerosis compared to metabolically healthy normal weight participants, supporting that MHO is not a harmless condition. This association, however, was mediated by metabolic risk factors at levels below those considered abnormal, suggesting that label of metabolically healthy for obese subjects may be an artifact of the cut-off levels used in the definition of metabolic health.”

Because researchers like to write in language only they understand, let me see if I can clarify that quote: Even if you’re “metabolically healthy,” if you’re obese you’re more likely to have some build up in your arteries. To the point it’s a concern? These researchers believe yes. By current standards? Eh.

This is a consistent finding in this type of research. Where it’s been given the term “subclinical atherosclerosis.” The researchers felt so strongly about their results, and this subclinical phenomenon, they believe the current standards of healthy blood work should probably be revised. From the other papers I’ve read, this subclinical arterial build up is, consensually, a concern for this population.

I want to also point out this study qualified people as obese if their BMI was over 25, not 30. Further supporting the researchers arguments. If you’re starting at a lesser BMI qualification point, then those who qualify are likely to be healthier. In other words, from a health perspective, it’s better to have some of your sample have a BMI between 25 and 30, compared to all of your sample having a BMI over 30. By U.S. standards, this paper could say “Metabolically healthy overweight and obese participants display a harmful condition.”

Next, from December 2013:

“Researchers reviewed the data of 61,386 individuals in eight separate studies from the past decade.  Each study observed adults defined as normal weight, overweight, and obese (body mass index or BMI of 30 or greater). Each study evaluated the individuals’ metabolic status, i.e. cholesterol levels, blood sugar levels, and blood pressure. The studies compared fatal and nonfatal cardiovascular events such as heart attack and stroke, as well as other causes of death, across the three weight categories.

The comparative risks for premature death in the three weight groups became especially apparent after 10 years of follow-up.

The key finding is that even in the absence high blood pressure or cholesterol (in other words, a metabolic problem), an obese person whose BMI is 30 or greater may be at 24% additional risk for cardiovascular event or premature death compared to a person of normal weight, says Dr. Retnakaran.”

I don’t want to make this some rigorous analysis. This is more of a food for thought post. (I’ll get to the eating in a second.) However, please note above, over sixty THOUSAND people were looked at in that study. (Full paper here.) This has been a contentious topic in the research world. I want to point out the studies I’m referencing are the most recent research, with huge sample sizes. The type of research you tend to place your faith most in.

Furthermore, this paper seemed to clear up a lot of the contention. Some studies have found this “healthy obesity” is nothing to worry about while others have found it is. If you read enough of the papers, you see it slowly come out that the research with longer follow ups, at least 10 years, are the papers which find an issue. In the above research, they found there weren’t many issues when you looked at the healthy but obese group from 0-10 years, but once you got to ~10, issues were clear. While being heavy with good blood work is ok in the short term, over time it can come back to haunt you. [1]

In September 2013 Harvard Health ran a story about healthy obesity. They covered some physicians who have looked into this. The physicians:

“…identified several characteristics of metabolically healthy obesity. These include a high BMI with

    • a waist size of no more than 40 inches for a man or 35 inches for a woman
    • normal blood pressure, cholesterol, and blood sugar
    • normal sensitivity to insulin
    • good physical fitness”

The above characteristics are damn near exactly the characteristics of what the fitness field has been saying for at least a decade: You can have a high BMI and not worry about it if you’re in good shape. Well, since September 2013 about 75,000 people say that’s probably not true. That, regardless of how you look or what type of weight you have on you, you probably want to give some careful thought to how much weight is on you, period.

Here’s one way to look at this. Going back to our hypothetical male, the 5 foot 10 inch, 200 pounder:

  • If you’re a low body fat percentage, say 8%, you’d have 16 pounds of fat on you.
  • If you’re 155 pounds (BMI of 22 – right in the middle for a “healthy weight”) at 8% body fat, you’d have 12.4 pounds of fat on you.

The point is no matter how shredded you are, given the same body fat percentage, the heavier you are the more fat you will ALWAYS have. Have you ever seen someone say “I went from X weight to Y weight with no gain in fat”? They often follow this up with “That’s right, I went from X to Y and stayed at the same body fat percentage.” They don’t realize their latter statement disqualifies their former.

  • If you go from 155 pounds to 180 pounds and stayed at 8% body fat, per above, you HAD to gain fat. 8% of 155 pounds will always be less than 8% of any number bigger than 155 pounds.

My theory is beyond a certain point, more fat is more fat. And, more than likely, more muscle isn’t always better. That there is probably some threshold you don’t want to cross. Once you do, more weight is more weight.

This seems like common sense. The body is full of these “lines.” Water is great, but too much can kill you. Aerobic exercise is amazing for our health, but marathon training isn’t. We all love the sun, until it burns us. Where is that threshold for our weight? Call me crazy now, but that good ole BMI equation seems to be some help.

[1] Like I said, I didn’t want to make this a dense post, but a few words on this research: I believe this study (one with over 60,000 subjects) was about as good as we currently have for this condition. That said, the researchers do a great job mentioning why more needs to be done. A lot of research has been done on this but it’s all been done slightly differently, and it’s all missed some factors.

Next, while the metabolically healthy obese and overweight were both found to have increased risks in some form or fashion, the increase in absolute risk for having a cardiovascular event, when you’re a metabolically healthy obese person, compared to a healthy normal weight person, was 0.7%.

I mention this 1) I’m sure for many, looking a certain way (“jacked”) will outweigh having a smaller risk of a heart attack 2) As a health professional, for now, you CANNOT say being obese is ok, under any condition. You cannot attack BMI, you cannot tell your clients or facebook followers to ignore how much they weigh. You can say “The research could be better, there seems to be a risk but overall it’s small, however, relative to a healthy, normal weight person, as far as we know, you increase your odds by a good amount of say, having a heart attack, when your body goes beyond a certain weight.”

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