Dr. Jennifer Pearlman, MD CCFP NCMP FAARM
Women’s health and wellness expert
Is the progressive weight gain associated with aging inevitable? This is the question that countless patients ask of me in frustration as despite their valiant efforts with diet and exercise –the pounds keep accumulating on their scales and the inches keep creeping onto their waists.
As we age, no doubt, our bodies are less responsive to the typical caloric equation of weight loss; i.e. less calories in and more calories out. Indeed, new science is revealing that age related weight gain has very little to due with caloric balance and much more to do with the altered physiology of the aging body and adverse environmental and lifestyle factors.
By the age of 30 years, the body begins to undergo a dramatic change in composition with a loss of our lean body muscle, comprised of functional bone and muscle, along with an increase in our fat mass. More and more food energy gets stored as body fat and fat stores are redistributed to the belly. This deep abdominal fat causes our waistline to expand and releases inflammatory mediators that threaten our health. Midlife weight gain continues in men until age 55 years and in women until 65 years, when the accumulation of body fat is out-paced by an accelerating loss of lean body mass.
Women are at higher risk of becoming obese then are men. An estimated forty-percent of Canadian women are now overweight or obese. In North America, we face a female fat epidemic.
The health risks of adulthood weight gain has not garnered adequate public attention. In women, weight gain after menopause leads to increased risk of heart disease, high blood pressure, diabetes, sleep apnea, osteoarthritis and death. Obesity in women is linked with several cancers and is the most important lifestyle factor that increases the risk of breast and endometrial (uterine) cancer. Women who gain more than 20 pounds from the age of 18 years to midlife double their risk of developing breast cancer as compared to those who maintain stable weight. Similarly, nearly 80% of endometrial cancer is diagnosed in women who are overweight.
A Qualitative Approach to Age-related Weight Gain
The growing problem of midlife weight gain is in part the result of a faulty understanding of the causes. The incongruence is centered on the adherence to a quantitative instead of a qualitative framework; thinking conventionally in terms of calories in our diet and pounds on our scale instead of the quality of our food and the composition of our bodies. Take for instance, a 100 calorie snack comprised of organic raw kale and almonds as compared to a calorically equivalent snack of processed food laden with refined sugars, trans-fats and chemical flavours and colours. For a given calorie count, the metabolic impact of these foods are dramatically different. And similarly, when it comes to body weight, a pound of muscle is clearly preferable to a pound of fat. Muscle being firm, formed in all the right places and functional while at the same given weight, fat tissue is larger in size, wiggles when we walk, expands our waistline and is toxic to our bodies.
So what underlies this new qualitative paradigm of midlife weight gain? The multi-factorial answer lies in the interaction between genetic predispositions with lifestyle and environmental factors. Age-related weight gain arises from the loss of vital factors; hormones, nutrients, sleep, insulin sensitivity and metabolic efficiency coupled with a gain in stress, gut bugs, and cumulative environmental toxic exposure. Let’s take a closer look at some of these novel risk factors.
Our DNA is not our Destiny but a Roadmap
As it turns out, the risk of obesity and diabetes is partially coded in our DNA. While several gene suspects have been previously identified, scientists have recently uncovered perhaps the king of obesity genes that directly links weight and metabolic dysfunction to environmental factors. Early this year, scientists confirmed a novel fat gene, IRX3, which increases the risk of diet induced obesity and diabetes. Their work showed that mice with 2 copies of the IRX3 gene when fed a high-fat diet faced a 50% increase risk of obesity and a 70% increase risk of diabetes.
Our Bugs Matter!
While gene-environment interactions confer increased risk of age-related weight gain, so to do our body’s bugs, collectively referred to as the microbiome. Yes- our bugs matter! In fact, they out number us 10 to 1. Indeed, only 10% of the genetic material inside our bodies belongs to us and the balance belongs to the bugs in our guts! The microbiome is comprised of bacteria that co-habitate our bodies, many of which are critical to our survival. Dysbiosis is the overgrowth of pathogenic or unfavourable bacteria and has been implicated in auto-immune disease, asthma, diabetes, cancer and obesity. Recent research has shown that gut bugs play a vital role in energy extraction, storage and expenditure and contribute to diet-related obesity. The high fat, high sugar Western diet triggers an overgrowth of a group of bugs known as the Firmicutes which are better equipped at harvesting the refined sugars that make up the Western diet, importing glucose into the body and converting it to fat. Studies have shown that compared to a low fat, high fiber diet, the Western diet yields loss of healthy gut bugs (such as bacteroidetes) and overgrowth of Firmicutes. So not only do our genes matter, but our bugs too can predict weight gain.
Obesogens: the Solution to Pollution is Dilution
Environmental factors have the potential to influence both the expression of our genes and the type and diversity of our bugs. Since the end of the Second World War, over 80,000 industrial chemicals have been pumped into our environment. The increase in synthetic chemical production has coincided with a dramatic rise in the prevalence of obesity. Mounting scientific evidence suggests many industrial chemicals are obesogens, having the potential to alter metabolic function and lead to weight gain. And as the solution to pollution is dilution; more obesogenic toxins yields more body fat. Persistent organic pollutants such as organo-chlorine pesticides and polychlorinated biphenyls (PCBs) have been strongly linked with metabolic derangements in humans including diabetes and obesity. These type of environmental hazards are found pervasively as pesticides on our produce and chemical agents in our plastics but also will bioaccumulate into the fat depots of large animals. The environment is not just chemically toxic, but also socially and physically. In our 24-7 connected worlds of incessant multi-tasking, we end up over-stressed and under-slept. Too much cortisol and insomnia contribute to weight gain and altered signaling making us more vulnerable to the relentless marketing of shelf-stable, readily accessible processed foods high in refined grains, trans-fats, and prone to consuming more liquid calories than ever before. Super-sized toxic waste.
Qualitative Solutions for Frustrated Dieters
So calorie counts don’t count. Instead, the qualitative new paradigm requires careful attention to novel risks for weight gain. Clearly, the stakes are set high in light of the significant health implications of weight gain after puberty. And so to the frustrated midlife dieter, I will encourage a rethinking of calories, a shift in the diet to focus on the building blocks to support lean body mass (health fats and lean protein), and a redesign of lifestyle to stress less, sleep better and manage environmental exposures. While we can’t fix our genes, we can restore the integrity of the microbiome and shape our environment to achieve the full potential encoded in our genes ….without the belly fat.