Visceral body fat essentials
Along those lines, they reported that an increased WHR (i.e., android obesity) was predictive of coronary heart disease, and they also went on to report that men with a high proportion of body fat were at a
significantly greater risk for the development of diabetes.
During this time, Ahmed Kissebah and his team from the University of Wisconsin in
Milwaukee published several papers that were fully in line with the observations of the Swedish researchers showing that the proportion of abdominal belly fat, estimated using
the WHF, was predictive of metabolic abnormalities increasing the risk of both type 2
diabetes and cardiovascular disease. These two research groups led the field of obesity
research providing early evidence that body fat storage patterns (assessed by simple methods such as WHR) were a key predictor of metabolic abnormalities and health risks.
Despite an explosion in obesity research and tremendous advances in technology, the
problem has only gotten worse. In a study jointly conducted in 2010, the International
Association for the Study of Obesity (IASO) and the International Obesity Task
Force (IOTF) estimated that approximately 1.5 BILLION people across the globe are
overweight, with over 475 million obese adults.
According to the World Health Organization (WHO), the prevalence of overweight and
obesity has further increased since the IASO/IOTF report was published just a few short years ago. In fact, the WHO reports that, in 2014, over 1.9 BILLION folks across the world are overweight, with over 600 million of those folks being classified as obese.
That’s over a 25% increase in obesity in less than 5 years.
According to data from the National Health and Nutrition Examination Survey, 2 out of
every 3 adults in the United States are overweight or obese, and over one-third of the adult population is obese.
In general, 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. Research has shown that storing excess visceral belly fat, referred to as abdominal obesity, is associated with a constellation of metabolic alterations and health conditions including :
• Insulin resistance and type 2 diabetes High triglycerides (e.g., high VLDL1 and VLDL2)
• Low levels of large HDL2 particles (the so-called “good” cholesterol)
• High levels of small, dense LDL particles (small, dense particles are considered
more detrimental than large, fluffy particles15)
• High levels of apolipoprotein B (which is considered a better predictor of
cardiovascular risk than the more commonly used LDL14)
• Cardiovascular disease
• Hypertension
• Certain cancers
• Sleep apnea
• Metabolic syndrome
• Unhealthy levels of inflammation
• Leptin resistance
The Skinny on Skinny Fat
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.
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.”
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 colleagues13 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
Conversely, it’s possible to be “obese” yet “metabolically healthy,” which involves
increased levels of body fat, low levels of visceral fat, a normal metabolic profile, and
high insulin sensitivity. Some refer to this as “fit but fat.”
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.
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.
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.
There appears to be a number of factors that contribute to excessive storage of belly
fat, including some that may be out of your control, including:
• Age
• Gender (e.g., men are more likely to accumulate fat in the android pattern)
• Sex hormones (e.g., low testosterone in males is associated with increased visceral belly fat) [Note that sex hormones may be modified by lifestyle and behavioral factors.]
• Genetics
• Ethnicity (e.g., African-American and Hispanic populations seem to be at a higher
risk)
• Central and peripheral nervous systems (e.g., endocannabinoid system)
Having said that, 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 of studies have examined the impact of exercise on visceral
fat, and while the exact amount (i.e., volume) and intensity is still being 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. 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.
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.
Stress Management
Excessive stress or the inability to cope with stress may also be a contributing factor to
central obesity. From a body composition standpoint, stress has been associated with
weight gain, which it may drive through multiple pathways:
1. Through eating behaviors and diet quality
2. Through biological processes
With regard to the latter, excess stress or the inability to cope with stress may contribute to storing excess belly fat (i.e., visceral fat). 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.
There are a number of potential explanations for the stress-cortisol-belly fat connection.
For instance, the enzyme (i.e., HSD) that “activates” cortisol from its inactive form (i.e., cortisone) is more prevalent in visceral fat than subcutaneous fat tissue. What’s more,
visceral fat tissue has greater blood flow and four times as many cortisol receptors (compared to subcutaneous). Even more, research shows that cortisol increases
lipogenesis, which is the process of fat synthesis and storage.
It’s important to note that the hormone cortisol is not inherently “bad.” In fact, it serves
very important physiological function. In the short-term, along with the catecholamines,
cortisol is essential for adaptation, homeostasis, and survival. For instance, cortisol (which belongs to the glucocorticoid family of hormones) has a profound effect on blood sugar regulation, as its role is to liberate glucose when blood sugar levels are low.
Obviously, that would be very important during acute periods of stress when energy is
needed (e.g., fasting, exercise).
However, issues arise when stress is long-lasting, which can have damaging effects on
the body and health. In excess, cortisol can negatively impact cardiovascular health,
body weight, energy levels, and wellbeing.
The impact of stress on eating behaviors and diet quality is a profound one, and stress has been associated with higher caloric intake, increased saturated fat and sugar consumption, and poor diet quality.
“Emotional eating” is defined as eating to relieve negative emotions (e.g., unhappiness, anxiety, or anger), and stress has been well documented as a key negative emotion involved in emotional eating. Emotional eaters typically consume more calories, they eat more frequently, and they indulge in greater amounts of highly palatable, highcalorie, sweet, high-fat foods in response to emotional stress.
It’s no secret that stress can be a “trigger” for overeating. In fact, research shows that around 70% of individuals increase their food intake during periods of stress.
Females, overweight individuals, and folks who think about food or body weight obsessively are more likely to eat when stressed.
As one might expect, research also shows that stress-induced eating typically involves
a predisposition for high-sugar and high-fat foods, which are “comfort foods” known to provide strong rewarding effects and reinforce snacking.
Studies have shown that emotional eaters may try to regulate the negative emotions
caused by everyday life through eating behavior, and while their chosen “foods” may provide short-term “comfort” from stress, they also drive appetite for these unhealthy
foods at the same time, which ups the risk of weight gain. The benefits on mood may
be fleeting, but for most people, the short-lived feelings of wellbeing may be sufficient to
promote repeated attempts to boost mood through stress eating patterns.
This pattern of stress-induced, emotional eating creates a negative, vicious,
perpetuating cycle of overeating and weight gain, followed by restriction, which again
leads to overeating and weight gain.
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).
Stress management can be tricky, but there are a number of things that you can start
practicing daily that can all contribute to healthy stress levels:
1. Yoga has been shown to exert powerful “anti-stress” effects and cortisol-reducing
capabilities.
2. Mindfulness meditation, which is a form of meditation where you focus your
awareness on your breathing and body in the present moment, has been shown
to lower both stress and cortisol levels.
3. Regular physical activity, managing finances, and healthy relationships can all
contribute to healthy stress levels.
4. Shinrin-yoku, which is also known as “forest bathing,” typically involves taking a
leisurely walk in nature. Forest bathing is commonly practiced for the purpose of relaxation and stress management, and studies show that it can reduce sympathetic nervous system activity (i.e., fight or flight), increase parasympathetic
nervous system activity (i.e., rest and digest), and lower cortisol levels.
In addition, there may be certain dietary supplements that can help reduce cortisol and
lower stress. While herbalists have known this for centuries, more and more research
suggests that certain herbs (i.e., adaptogens) may be helpful in combating cortisol and
improving stress levels. For instance, Rhodiola rosea has been shown to decrease cortisol levels, exert an anti-fatigue effect, increase the ability to concentrate, and lower
stress. Another adaptogenic herb, Ashwagandha has been shown to have a dramatic cortisol lowering effect.
Brings whole new meaning to the phrase, “Take a chill pill,” doesn’t it?
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.
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.
In addition, excessive consumption of saturated fats also appears to be linked to
visceral fat storage. Conversely, researchers have shown that replacing saturated
fats with more monounsaturated fats (i.e., Mediterranean diet) prevents visceral belly fat gain despite consuming an equal number of calories. Additionally, adherence to the Mediterranean diet has been shown to be associated with lower waist circumference values independent of body weight in both men and women.
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. 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.
While overall nutritional factors like those outlined above seem to play a role, it’s a bit
less clear as to whether body fat distribution patterns can be influenced by specific
foods/nutrients. Having said that, the following lists of foods can be a solid foundation to
be used along with an overall healthy diet, regular physical activity, and routine stress management strategies to help fight visceral belly fat.
1. Cold-Water Fatty Fish
Cold-water, fatty fish (e.g., salmon, mackerel, herring, anchovies, sardines) are rich in omega-3 fatty acids,
which boost mood and ease anxiety and stress.
In one study, researchers from France evaluated the effects of supplementation with omega-3 fatty acids on the stimulation of the sympathetic nervous
system and stress hormones. They found that three weeks of omega-3 supplementation
significantly blunted cortisol and sympathetic nervous system activity when participants
were challenged with a mental task.
In a randomized controlled trial published in the Journal of the International Society
of Sports Nutrition, researchers from Gettysburg College assessed the effects
of supplementation with omega-3 fatty acids on cortisol levels. After 6 weeks of
supplementation, they found that participants’ levels of cortisol were reduced. Not only
that, participants who supplemented with fish oil also significantly reduced body fat and
increased calorie-burning lean mass.
As previously noted, chronically elevated levels of cortisol may specifically contribute
to abdominal obesity. What’s more, elevated cortisol levels have been shown to be
positively associated with abdominal sagittal (waist) diameter and waist-to-hip ratio, two
indicators of visceral fat and abdominal obesity.
According to a review study published in the journal Nutrients, South Australian researchers concluded that there is “considerable” evidence from animal studies indicating that supplementation with omega-3 fats (i.e., EPA, DHA) can reduce body
fat, in particular visceral belly fat. The researchers cited several studies where
omega-3 fats had a protective effect against fat accumulation. In other words, in studies
where animals overfed high-fat, high-calorie diets supplemented with omega-3s, they
experienced significantly less belly fat accumulation compared to without.
That’s great, but what about humans like you and I? Good news. There is indeed
evidence—and it’s growing to boot—indicating that increasing the intake of omega-3
fatty acids (by 0.3 – 3.0 grams per day) can reduce body fat, particularly abdominal fat, in overweight and obese folks.
For instance, in a study published in The American Journal of Clinical Nutrition,
researchers from Spain found that abdominal obesity was inversely related to the
omega-3 (particularly DHA) intake.71 In a follow-up study, the researchers found that
omega-3 intake was inversely related to the size of fat cells in overweight and obese
adults. Taken together, these findings suggest that a higher omega-3 intake is
associated with reduced visceral belly fat as a result of a decrease in the size of fat cells.
In a randomized controlled trial published in the journal International Journal of
Obesity, researchers from Iceland investigated the effects of including seafood and fish oil as part of a reduced-calorie diet on weight loss in young overweight adults. The
researchers found that the addition of fatty fish (5.3 ounces of salmon 3 times per week)
or fish oil (1.5g of EPA and DHA per day) for 8 weeks resulted in significantly greater
weight loss and reductions in waist circumference (i.e., visceral fat) compared to diet alone (without the addition of omega-3 fats).
Even more compelling, a recent meta-analysis of randomized controlled trials published
in the journal PLoS One provides additional evidence that omega-3 fats may reduce
visceral belly fat. For instance, 8 studies (including 624 participants) investigated the effects of fish oil supplementation on waist circumference combined with a weight-loss program (e.g., diet, exercise). The results demonstrated that fish oil had a significant
additional effect in reducing waist circumference, a measure of abdominal obesity, in combination with a weight-loss program.
In other words, fish oil plus diet and/or exercise had a greater effect than diet and/
or exercise alone. What’s more, this comprehensive review also found that fish oil
supplementation had a significant effect on waist-to-hip ratio, another important metric of visceral fat and overall health. The results of 17 different studies (with over 1,000
participants) showed that supplementation with omega-3 fats significantly reduces waistto-hip ratio both as standalone treatment and when combined with a weight-loss program.
Taken together, the researchers concluded that folks “may benefit from reducing
abdominal fat with fish oil supplementation especially when combined with life
modification intervention” (e.g., diet and exercise).
2. Pasture-Raised Meat & Eggs
When it comes to fat loss, there’s arguably not a generally more effective nutrition strategy than optimizing protein intake. Research illustrates quite clearly and convincingly that increasing dietary
protein intake to at least TWICE the RDA (i.e., ≥ 1.6g/
kg or 0.72 g/lb) may be “metabolically advantageous,” particularly for individuals looking to improve body
composition as well as physically active folks.
Higher protein diets have been shown to:
• Accelerate fat loss and spare lean body mass while following a reduced-calorie diet.
• Attenuate weight regain and contribute to long-term weight maintenance.
• Optimize 24-hour muscle protein synthesis and facilitate the maintenance or
building of muscle mass, which is critical for preserving metabolic rate and
preventing weight regain.
• Boost metabolic rate.
• Preserve metabolic rate after weight loss.
• Increase satiety and improve appetite control.
• Improve carbohydrate metabolism and glycemic regulation.
In addition, there’s evidence that protein intake may be particularly effective against belly fat. For instance, in a study published in The American Journal of Clinical Nutrition,
researchers from Denmark assessed the diet and macronutrient intake on waist
circumference among a large group (over 40,000) of people over the course of 5 years.
They found that, besides fruit and vegetable intake, only protein intake (specifically, animal protein) was inversely associated with belly fat.
In addition, a recent study published in the journal Nutrition & Metabolism demonstrated
that the amount of quality protein consumed was inversely related to abdominal fat. In
other words, people who ate more high-quality protein had less belly fat. And when it
comes to quality protein (e.g., amino acid profile, digestibility), animal proteins (such as
meat and eggs) are at the top of the list.
When buying meat and eggs, it’s best to purchase products from pasture-raised animals
whenever possible. In a recent systematic review and meta-analysis published in the British Journal of Nutrition, a group of researchers critically analyzed data from 67 different studies comparing the composition of organic (i.e., grass-fed, pasture-raised) and nonorganic (i.e., conventional) meat products. They found that meat from pasture-raised animals contained 47% more omega-3 fatty acids than conventional meat products.
Further, several studies have examined the nutritional content of eggs from pasture raised hens compared to eggs from commercial caged chickens. In a study conducted by researchers in Penn State’s College of Agricultural Sciences, eggs from pasture raised hens were shown to have 2 ½ times more omega-3 fats and less than half the ratio of omega-6 to omega-3 fats.
3. Pasture-Raised Dairy
Like meat and eggs, dairy (e.g., yogurt) is high-quality source of protein. Numerous studies have shown
an inverse association between dairy intake and abdominal obesity. Even more interesting—and perhaps
counterintuitive—is that recent research has shown that a high intake of dairy fat (e.g., full-fat milk and yogurt) is associated with less belly fat.
Also like meat and eggs, it’s best to choose products from organic, pasture-raised
animals when possible. A recent systematic review found that organic milk was
significantly higher than conventional milk in omega-3 fats, by an estimated 56% more, organic milk contained an estimated 41% more conjugated linoleic acid (CLA).
CLA has been shown to improve body composition (i.e., reduce body fat, increase lean body mass), enhance immunity, and promote a healthy inflammatory response. Even more, there is also some evidence that CLA may reduce visceral belly fat.
