Tag Archives: supplements

The Skinny on “Skinny Fat” (Normal-Weight Obesity)

16 Nov

Tim Skwiat, MEd, CSCS, Pn2

There’s a common misconception that body weight is a reliable and accurate depiction of health. However, the number on a scale says very little about one’s level of fitness, body fatness, fat storage patterns, and levels of lean body mass.

Typically, an “ideal” or “normal” weight is calculated as a ratio of body weight to height. The most commonly used tool is called the Body Mass Index (BMI), which is a person’s weight (in kilograms) divided by his/her height (in meters) squared (i.e., kg/m2). Using this ratio, the BMI separates folks into the following categories:

  • Underweight (BMI < 18.5)
  • Normal weight (BMI 18.5 – 24.9)
  • Overweight (BMI 25 – 29.9)
  • Obese (BMI > 30)

Hence, the notion of “normal” weight is born, but as mentioned above, there are many limitations associated with the BMI and using this avenue to assess health and fitness. Along those lines, recent research suggests that where folks store body fat—even if they fit into the “normal weight” category—may drastically increase their risk of disease and death.

In a study published in the journal Annals of Internal Medicine, a group of researchers led by Dr. Francisco Lopez-Jimenez, director of preventive cardiology at the Mayo Clinic, examined 14 years worth of data including over 15,000 study participants to determine the potential connection between “normal-weight obesity” and the risk of cardiovascular disease and death. They found that folks who are “normal weight” but store an excessive amount of fat in their mid-sections were more than twice as likely to die from cardiovascular disease compared to “obese” people whose body fat was more equally distributed throughout their bodies.1

It’s not like obese folks have a reduced risk of morbidity and mortality either. In fact, as you might imagine, traditionally defined obesity is a substantial, independent risk factor for cardiovascular disease, and it’s associated with diabetes, high blood pressure, sleep apnea, and a host of metabolic issues.2 This research suggests that “normal-weight obesity” appears to be even worse than that.

To put the increased risk of disease and death into perspective, Dr. Lopez-Jimenez said, “Being normal weight with mid-section obesity is comparable to smoking a half to a full pack of cigarettes daily.”

While the effect of “normal-weight obesity” on mortality has gained a significant amount of attention, it shouldn’t come as a complete shock. Previous research has shown that abdominal obesity is associated with a “constellation of metabolic abnormalities,” including:3,4

  • High triglycerides
  • Low levels of “good” cholesterol (i.e., HDL)
  • High levels of apolipoprotein B (which is considered a better predictor of cardiovascular risk than the more commonly used LDL5)
  • Small, dense LDL and HDL particles (small, dense particles are considered more detrimental than large, fluffy particles6)
  • Unhealthy levels of inflammation
  • Insulin resistance
  • Poor carbohydrate tolerance and metabolism
  • Leptin resistance

A number of important lessons and practical applications can be gleaned from this research and information. For one, it’s possible to be “normal weight” and “metabolically obese,” which Dr. Lopez-Jiminez and colleagues4 have defined as having:

  • Normal BMI
  • High visceral fat
  • High body fat percentage
  • Low muscle mass
  • Reduced insulin sensitivity
  • High blood sugar
  • High triglycerides
  • Reduced HDL cholesterol

Secondly, using a ratio of body weight to height (i.e., BMI) can be a relatively poor indicator of health and fitness. With that in mind, it’s important to use other measurements to determine health risk. While body composition testing (i.e., ratio of fat to lean mass) is arguably the most accurate means to discern health status, using waist circumference and waist-hip ratios may be alternative options.7–9

In general, women who have a waist circumference greater than 35 inches and men whose waist measurement is 40 inches or more are considered to have “central obesity” and be at “substantially increased” risk for cardiovascular disease and metabolic complications. With that said, according to the World Health Organization (WHO), women with a waist circumference greater than 31.5 inches and men with a waist circumference greater than 37 inches are at an “increased” risk for metabolic complications.10

Some research suggests that waist-hip ratio may be an even better predictor of health risk than waist circumference. According to the WHO and other professional health organizations, abdominal obesity is defined as a waist–hip ratio of 0.85 for females and 0.9 or more for men, and folks that fit into these categories are considered to be at “substantially increased” health risk because of their fat distribution.10,11

There appears to be a number of factors that contribute to excessive storage of belly fat. While genetics play a role, there are several modifiable lifestyle and behavioral factors, well within your control, that can be addressed to prevent the accumulation of and/or reduce the amount of existing visceral fat.

Exercise. A sedentary lifestyle, an overall lack of physical activity, and low levels of fitness are associated with abdominal obesity. As mentioned above, it should be noted that “normal-weight obesity” is typically associated with lower levels of muscle mass. This is often described as being “skinny fat.”

Fortunately, a number a studies have examined the impact of exercise on visceral fat, and while the exact amount (i.e., volume) and intensity is still be investigated, a substantial body of evidence suggests that a combination of resistance training and aerobic conditioning (including moderate and intense cardiovascular activity) may be optimal to reduce/attenuate abdominal obesity.12–15 The additional advantage to including resistance training is that it is the primary means by which to increase muscle mass, and it is also very effective at improving carbohydrate tolerance and insulin sensitivity.16,17

According to the American College of Sports Medicine (ACSM), a combination of moderate- to high-intensity exercise performed for a total of at least 250 minutes per week (i.e., 5 – 6 days of 45 – 60 minutes of exercise) is associated with significant weight loss.18

Nutrition. Not surprisingly, nutrition behaviors and food intake appear to have a direct impact on central obesity, and what’s more, studies that combine regular physical activity with diet interventions (i.e., resistance and/or aerobic exercise PLUS a reduced-calorie diet) result in even more significant reductions in visceral fat than either individually.12,19 As cited above, poor insulin sensitivity and carbohydrate tolerance coincide with excessive abdominal obesity, and there’s evidence to suggest that diets rich in refined carbohydrates (e.g., sugar-sweetened beverages) may selectively promote the storage of belly fat.20,21 In addition, excessive consumption of saturated fats also appears to be linked to visceral fat storage.22

Perhaps overtly obvious, long-term energy excess (i.e., overconsumption of calories) also leads to increases in overall body fatness and increases in abdominal obesity, and along those lines, research suggests that reduced-calorie diets (regardless of macronutrient composition) are effective at decreasing abdominal obesity.23,24 With that said, there is evidence that higher-protein (i.e., > 0.5 grams of protein per pound of body weight per day), “controlled carbohydrate” (i.e., <40% of calories from carbohydrate) reduced-calorie diets may be more effective at reducing visceral fat.25–28

Stress management. Excessive stress or the inability to cope with stress may also be a contributing factor to central obesity. You may be familiar with the “stress hormone” cortisol, which appears to have a direct connection to fat accumulation, and in particular, abdominal fat. Studies have shown that folks with high waist-hip ratios tend to have poor coping skills and secrete more cortisol when faced with a stressful situation. This suggests a relationship between cortisol and abdominal fat accumulation, and additional studies have identified a similar association between cortisol concentrations, coping skills, chronic stress, and excess belly fat.29,30

There are a number of potential explanations for the stress-cortisol-visceral fat connection. For instance, the enzyme (HSD) that “activates” cortisol from its inactive form (i.e., cortisone) is more prevalent in visceral fat than subcutaneous fat tissue.31 What’s more, visceral fat tissue has greater blood flow and four times as many cortisol receptors (compared to subcutaneous).30

It’s worth noting that there are a number of factors that can contribute to the stress equation—and subsequently, influence the release of cortisol—including psychosocial stressors, food intake, sleep quality and quantity, exercise, and more. Thus, it’s a good idea to examine your overall “stress web” to identify how various domains (e.g., physical, mental, emotional, environmental, financial, spiritual) may contribute to your overall stress levels (i.e., allostatic load).

While stress management can be tricky, yoga, meditation, mindful breathing (i.e., deep belly breathing), healthy levels of physical activity, optimizing sleep, purposeful relaxation, managing finances, and cultivating healthy relationships can all contribute to maintaining healthy stress levels. What’s more, there are certain herbs called adaptogens (e.g., Rhodiola Rosea; Relora®, which is a combination of Magnolia bark extract and Phellodendron bark extract) that may be helpful in reducing cortisol, improving stress levels, and promoting resilience.32,33 Also, phosphatidylserine may blunt cortisol release, reduce stress, and help promote an optimal hormonal status.34

Supplementation. In addition to the suggestions above, there may be additional nutrients that have a beneficial impact on central obesity. Of course, any dietary supplement that can promote a negative energy balance (e.g., increase energy expenditure, reduce calorie intake) has the potential to reduce visceral fat. There is also some evidence that supplementation with conjugated linoleic acids, fatty acids found in small amounts in dairy and meat, may preferentially reduce abdominal fat (i.e., waist circumference) in populations with central obesity.35,36

Take-Home Points

  • Using one’s body weight (and therefore, the scale) as the primary end point for assessing health and fitness may be unreliable and inaccurate.
  • “Skinny fat” (i.e., normal-weight obesity), which is characterized by a relatively high body fat percentage, excess visceral fat, and low levels of muscle mass, may put one at significantly greater health risk than folks who are “fat and fit” (i.e., metabolically healthy but overweight/obese).
  • While using the scale is one way to assess progress, consider using other measurements (e.g., body composition testing, circumference measurements, waist-hip ratios) to paint a more comprehensive picture of levels of body fat, fat storage patterns, and levels of lean body mass.
  • In addition to some factors that may be out of your control (i.e., genetics), there are a number of behavioral factors, well within in your control, that you can modify to reduce visceral fat or attenuate the risk of developing it in the first place.
  • Consider your current physical activity patterns, nutrition behaviors, and stress management tactics and how those areas may be playing a role in your health and fitness. If you could work on just one of those areas, which would it be? More specifically, what’s one thing that you might consider doing more of in one of these domains?

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References:

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