Time to act on obesity: why is it so difficult to lose weight?
Let me introduce you to Amanda. You’re just meeting her for the first time but chances are you’re already making assumptions
about how much she eats and how little she exercises
because she’s obese.
But I’m about to show you that there’s much more than meets the eyes when it comes to obesity. There are lots of Amanda’s out there
and they need treatment.
Maybe you’re one of them or maybe you know an Amanda.
It’s time to act on obesity. But in order to do so effectively,
we need to understand obesity.
It’s generally accepted that body weight is determined by a pretty simple formula.
We call it the energy balance equation and it works like this.
If the number of calories that you consume equals the number of calories that you burn, your weight remains the same.
If you consume more than you burn, you gain weight. And if you burn more than you consume, you lose weight. Most people think that those of us who properly manage our energy balance remain lean.
Whereas those of us like Amanda who eat too much and exercise too little become obese. We view obesity as a lifestyle choice and the cure for it is simple, eat less and exercise more.
This may sound logical but it’s wrong. Let me explain.
First, let’s talk about the set point. No, I’m not talking about the point in a tennis match when one player is about to beat the other.
I’m talking about a theory that says that no matter what you consciously want your weight to be, your brain has its own sense
of how much body fat it should have on board.
And it has a complex system in place that very precisely regulates
your energy intake and expenditure to keep you within a so-called
setpoint range for body fat.
So that whole energy balance equation, it’s not something that you control voluntarily. Your brain regulates your calories in
to your calories out for you.
For your brain to do this, it needs to know how much energy
you have on board at all times, and it knows this by listening
to hormones like leptin, which is made in your body fat.
You can think of it like a car. Leptin is the gas gauge that tells your brain, how much gas is in your tank. But leptin is just one piece of the puzzle. You’ve got a whole bunch of other hormonal signals and senses that are involved too.
Your bones, muscles, pancreas, liver, GI tract and sensory organs,
they all play a role, communicating with your brain to give it the information it needs to do its job.
But that’s more detailed than we need for this conversion. The point is that you have a complex system in place that regulates you to within a set point range for body fat.
So what happens if Amanda decides to lose weight by going on a diet.
After all, people with obesity should eat less, right?
Here’s what happens. She loses weight but her hormone levels change. Her brain hears this, and it starts acting to restore whatever body fat she’s lost.
She feels hungrier, and although she doesn’t know it, she is also burning fewer calories than before. You see the setpoint is usually
a one-way street.
Once it’s been elevated the brain works to defend it, just as vigorously as it would a lower set point. Amanda’s brain doesn’t know
that she needs to lose weight.
It only knows to defend her current set point. Back to our car analogy.
Amanda can’t help but look for a gas station to refuel when she sees that her gas gauge is low.
At the same time, she becomes more fuel-efficient burning less energy than before. This might explain why treating obesity
with diet and exercise so often fails to produce the desired results.
It’s sort of like telling Amanda that she needs to be a more careful driver when the real problem is that she needs a mechanic to fix her car. Okay.
So if we’ve all got this complicated system in place that prevents us from losing weight, why doesn’t it also protect us from gaining weight
and developing obesity in the first place?
How can we explain the obesity epidemic?
Getting back to Amanda, why did she develop obesity?
The answer is that it takes a perfect storm to cause an obesity epidemic like the one we’re seeing now, and it’s our modern environment that places us and Amanda directly in the path of that storm.
Well, there’s no single cause for the rising rate of obesity.
Changes to the chemical and nutrient content of our food, the so-called western diet, a decrease in physical activity, increased levels of stress, inadequate and disrupted sleep, and more widespread use of medications that promote weight gain, all play a role.
Our unique genetics and developmental histories cause each of us to respond differently to these elements of the modern environment, and some of us, like Amanda, respond by sending hormonal signals
that elevate our set point for body fat.
It’s not that Amanda’s system has stopped working. It’s just that it’s working to regulate her to a set point that’s too high.
So you can think of obesity as a biological response
to the modern environment, a disease where the body dis-regulates
to a body fat set point that is too high.
Back to our car analogy. The size of Amanda’s gas tank has expanded
so she carries around too much fuel. It’s time to stop blaming Amanda for her obesity.
What is obesity?
The most basic function of bodily fat is self-storage of food reserves.
In prehistoric times, natural selection favored genotypes that could endure harsh conditions by stocking the most fat.
With chronic malnutrition being the norm for most of human history,
genetics evolved to favor fat storage. So when did body fat become problematic?
The negative impacts of being overweight were not even noted in the medical literature until as late as the 18th century.
Then, technological advances coupled with public health measures
resulted in the betterment of the quantity, quality, and variety of food.
Sustained abundance of good food enabled a healthier population
to boom economically.
Output increased, and with it, leisure time and waistlines.
By the mid 19th century, being excessively overweight, or obese,
was recognized as a cause of ill health, and another century later, declared deadly.
What is the distinction between being overweight and being obese?
A calculation called the BMI breaks it down for us. For example, if someone weighs 65 kilograms and is 1.5 meters tall, they have a BMI of about 29. Obesity is a condition of excess body fat that occurs when a person’s BMI is above 30, just over the overweight range of 25 to 29.9,
While BMI can be a helpful estimate of healthy weight, actual body fat percentage can only really be determined by also considering information like waist circumference and muscle mass.
Athletes, for instance, have a naturally higher BMI. So how does a person become obese? At its most basic, obesity is caused by an energy imbalance. If the energy input from calories is greater than the energy output from physical activity, the body stores the extra calories as fat.
In most cases, this imbalance comes from a combination of circumstances and choices. Adults should be getting at least 2.5 hours of exercise each week, and children a whole hour per day.
But globally, one in four adults and eight out of ten adolescents
aren’t active enough. Calorie-dense processed foods and growing portion sizes coupled with pervasive marketing lead to passive overeating.
And scarce resources and a lack of access to healthy, affordable foods creates an even greater risk in disadvantaged communities.
Yet, our genetic makeup also plays a part. Studies on families and on separated twins have shown a clear causal hereditary relationship to weight gain.
Recent studies have also found a link between obesity
and variations in the bacteria species that live in our digestive systems.
No matter the cause, obesity is an escalating global epidemic.
It substantially raises the probability of diseases, like diabetes,
heart disease, stroke, high blood pressure,
It affects virtually all ages, genders, and socioeconomic groups
in both developed and developing countries. With a 60% rise in child obesity globally over just two decades, the problem is too significant to ignore. Once a person is obese, the climb to recovery becomes progressively steeper.
Hormonal and metabolic changes reduce the body’s response to overeating. After losing weight, a formerly overweight person burns fewer calories doing the same exercises as a person who is naturally the same weight, making it much more difficult to shed excess fat.
And as people gain weight, damage to signaling pathways makes it increasingly difficult for the brain to measure food intake and fat storage. There is, however, some evidence that well-monitored, long-term changes in behavior can lead to improvements in obesity-related health issues.
And weight loss from sustained lifestyle changes,
or invasive treatments like bariatric surgery, can improve insulin resistance and decrease inflammation.
What was once an advantage for survival is now working against us.
As the world’s population continues to slow down and get bigger,
moving, and consciously eating our way towards a healthier weight
is essential to our overall well-being. And with the epidemic affecting every country in the world for different socioeconomic reasons,
obesity cannot be seen as an isolated issue.
More global measures for prevention are essential to managing the weight of the world.