Skinny Fat

Written by Dr. Steve Chaney on . Posted in current health articles, Exercise, Food and Health, Health Current Events, Healthy Lifestyle, Nutritiion, Obesity

Overweight Vs. Obesity

Author: Dr. Stephen Chaney

skinny fatAre you skinny fat?  Weight loss season is upon us. Many of you are jumping on your bathroom scales so that you can decide how much weight you need to lose this year. For some the motivation for these New Year’s resolutions to lose weight is purely cosmetic. You just want to look better. For others the motivation for losing weight is better health. Obesity is a killer. It is associated with increased risk of diabetes, heart attack and stroke – and that’s just the tip of the iceberg.

But what if your bathroom scale says that you are normal weight? Are you off the hook? Maybe not. A recent study suggests that if you are normal weight but have central obesity (a fancy scientific term for belly fat), you are more likely to die prematurely than someone with normal fat distribution regardless of how overweight they are. That’s a pretty scary thought. It has even generated a new risk category called “skinny fat”.

How Can You Be Obese Without Being Overweight?

In recent years there has been some controversy about the health risks of obesity. Part of that controversy has arisen because obesity can be defined in multiple ways. Most of us simply hop on the scale and rely on actuarial tables to tell us what a healthy weight is for our height. Scientists, on the other hand use two very different measures of obesity.

#1 is Body Mass Index or BMI.BMI is a person’s weight in kilograms (kg) divided by his or her height in meters squared. By this measure:

  • Normal body weight is defined as a BMI of 18.5-24.9 kg/m2.
  • Overweight is defined as a BMI of 25-29.9 kg/m2.
  • Obesity is defined as a BMI of ≥30 kg/m2.

#2 is waist to hip ratio or WHR. WHR is a measure of central adiposity (belly fat). By this measure:

  • Obesity is defined as excess central adiposity (excess belly fat), which is a waist to hip ratio ≥0.85 in women and ≥0.90 in men.

In general BMI and WHR correlate. However:

  • 11% of men and 3.3% of women are normal weight according to BMI measurements, but have excess belly fat according to WHR measurements.These are the individualswho are obese according to their WHR measurements without being overweight according to their BMI measurements. These are the individuals often referred to as “skinny fat”.
  • There are similar percentages of men and women who are overweight or obese according to BMI measurements, but have low WHR measurements. These are often referred to as “pear shaped” obese individuals to distinguish them from the “apple shaped” obese individuals with a lot of belly fat.

Being Skinny Fat Can Kill You

obesity vs. overweightNumerous studies have shown that “apple shaped” obesity is much more likely to be associated with disease and premature death than “pear shaped” obesity, but there have been very few studies comparing health outcomes for normal weight individuals who have excess belly fat (people who are “skinny fat”) with health outcomes of overweight and obese individuals. This study (Sahakyanet al, Annals of Internal Medicine, 2015 Nov 10 doi: 10.7326/M14-2525) was designed to fill that void.

These scientists analyzed data from the National Health and Nutrition Survey III (NHANES III). NHANES III collected BMI, WHR and health data from 15,184 Americans (52.8% women) aged 18 to 90 years (average age 45) and followed the study participants for 14.3 years. By that time 3222 of them had died, with 1413 of those deaths being due to heart disease. The results were enlightening:

  • Normal weight individuals with excess belly fat (“skinny fat” individuals) were 1.5 – 2.0 fold more likely to die during the 14.3 year follow up period than individuals who were normal weight and had little belly fat (“skinny lean” individuals). This was expected because this had been shown in several previous studies.
  • However, the surprising finding was that normal weight individuals with excess belly fat were also more likely to die than individuals who were overweight or obese. Specifically:
  • Men who were “skinny fat” were 2.2 – 2.4 fold more likely to die prematurely than men who were either overweight or obese, but did not have excess belly fat (men with a “pear shaped” fat distribution). “Skinny fat” women were 1.3 – 1.4 fold more likely to die prematurely than overweight or obese women with “pear shaped” fat distribution.
  • Men who were “skinny fat” were even slightly more likely to die prematurely than overweight or obese men with excess belly fat (men with “apple shaped” fat distribution). “Skinny fat” women were just as likely to die as overweight or obese women with “apple shaped” fat distribution.
  • When they looked at deaths due to cardiovascular disease the results were essentially the same.
  • These results were novel and should, perhaps serve as a wake-up call for normal weight individuals with excess belly fat.

The authors concluded:

  • “Our analysis of data…show that normal-weight U.S. adults with central obesity [excess belly fat] have the worst long-term survival compared with participants with normal fat distribution, regardless of BMI category.”
  • “To our knowledge, our study is the first to show that normal-weight central obesity, measured by WHR, is associated with an increased risk of cardiovascular mortality.”
  • “Our findings suggest that persons with normal-weight central obesity may represent an important target population for lifestyle modification and other preventative strategies.”

Why Is Being Skinny Fat So Dangerous?

health riskAs the authors of this study pointed out, it is well established that excess belly fat is associated with:

  • Insulin resistance, which can lead to diabetes and predispose to heart disease.
  • High triglycerides and high levels of “bad” cholesterol, which can lead to heart disease.
  • Inflammation, which can lead to a number of deadly diseases.

The metabolic effects of excess belly fat are sufficient to explain why someone who is “skinny fat” is more likely to die prematurely than someone who is “skinny lean”. However, the effect of excess belly fat is not sufficient by itself to explain why a “skinny fat” individual is more likely to die prematurely than someone who is overweight or obese.

To understand this we need to recognize that both fat and muscle contribute to body weight (and to BMI). The “skinny fat” individual has more fat mass AND less muscle mass than a “skinny lean” individual of the same weight. That is a huge factor because metabolically speaking muscle is protective. It opposes all of the bad metabolic effects of belly fat.

Simply put, being “skinny fat” is extremely dangerous because you have increased all the bad metabolic effects of excess belly fat, ANDyou have decreased the protective metabolic effect of muscle mass.

How Do You Go From Being “Skinny Lean” To “Skinny Fat”?

Most of us were lean in our younger years. For those of us who end up as “skinny fat” as we age, it is pretty obvious that there are two processes going on simultaneously.

#1: Loss of Muscle Mass:It would be easy to say that becoming “skinny fat” is a natural part of aging. The natural tendency is to loose muscle mass and replace it with fat mass as we age. If we “just go with the flow” all of us will end up being “skinny fat” at some point. However, the loss of muscle mass as we age is accelerated by our sedentary lifestyle and our diet (more on that below).

#2: Gain of Belly Fat:To some extent whether we store excess fat as “pears” or “apples” is genetically determined. However, what we eat can also exert a major influence. For example:

  • Alcohol: The term “beer belly” says it all. Excess alcohol consumption is associated with an increase in belly fat. Once you understand the metabolism of alcohol the explanation is pretty simple. Alcohol causes blood sugar to drop, which increases appetite. Alcohol also interferes with our judgement, which can cause us to make poor food choices.
  • Excess saturated fat tends to be stored preferentially as belly fat.
  • Excess sugars and simple carbohydrates are rapidly converted to fat stores and stored as belly fat.

What Can You Do If You Are Already Skinny Fat?

gain muscle massLet’s start with what you shouldn’t do. You should not go on a reduced calorie weight loss diet to get rid of your excess belly fat. The last thing you want to do is to end up being underweight with excess belly fat! Here is what you should do:

#1: Increase Your Muscle Mass:I said that loss of muscle mass was a natural part of aging. I didn’t say that it was an inevitable part of aging. If you want to prevent or reverse loss of muscle mass you need to:

  • Get really serious about exercise. I’m talking about 30 minute workouts at least 3-5 times per week. These workouts need to include strength training as well as aerobics and flexibility exercises. I would suggest you ask your health professional what kind of exercise program is best for you and start your exercise program under the guidance of a personal trainer or physical therapist.
  • Make sure that your diet contains enough protein and enough of the essential amino acid leucine to maximize the gain of lean muscle mass following your workouts. I have covered the latest age-appropriate recommendations in, leucine and muscle gain, a previous “Health Tips From The Professor.”

#2: Lose Your Belly Fat:To some extent you will start to lose your belly fat naturally if you follow the recommendations above. In addition, you will want to:

  • Drink alcohol in moderation.
  • Make food choices that allow you to replace saturated fat with monounsaturated fat and polyunsaturated fats, especially the omega-3 polyunsaturated fats.
  • Replace excess sugars and simple carbohydrates with complex carbohydrates from fresh fruits and vegetables along with modest amounts of whole grain foods.

The Bottom Line

  • A recent study has shown that being “skinny fat” (having normal body weight, but excess belly fat) is more likely to result in premature death than if you were overweight, or even obese.
  • The most likely explanation for this alarming statistic is that someone who is “skinny fat” has excess belly fat, which predisposes to a number of diseases, and a loss of muscle mass, which protects against those same diseases.
  • If you are overweight or obese, you need to reduce your caloric intake to lose weight. However, if you are “skinny fat”, you don’t want to reduce your caloric intake. You need to change your exercise and diet habits.
  • Loss of muscle mass and gain of fat mass is a normal part of aging. However, you can slow or reverse the age-related loss of muscle mass with an exercise program and enough protein and leucine in your diet to maximize the effects of that workout program (details above).
  • You can prevent or get rid of excess belly fat by:
  • Following the exercise program and nutritional support of that exercise program described above.
  • Making food choices that replace saturated fats with monounsaturated fats and polyunsaturated fats, especially omega-3 polyunsaturated fats.
  • Replacing foods high in sugar and simple carbohydrates with fresh fruits and vegetables and whole grains in moderation.

 

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)

  • Doug

    |

    Another way to be obese and really not be is to pay attention to the overly simplistic BMI reading. I am muscular 5′ 7″ 185 lbs and am obese by the BMI guidelines. I have a .98 WHR.

    Reply

    • Dr. Steve Chaney

      |

      Dear Doug,
      You are absolutely right. It’s too bad there aren’t more like you.
      Dr. Chaney

      Reply

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Latest Article

A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

 

low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?

 

How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

 

Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

 

What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

 

low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

 

  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

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.

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