We all come in different shapes and abilities. We may not be able to have the genetic alibility to be professional runners or weightlifters, but we can move our body like a runner or a lifter.
Our genetics will determine our body shape and health to a certain point; thereafter the choices we make are entirely responsible for our wellbeing.
Nature and Twin Studies
It is difficult to separate nature from nurture regarding body shape, many studies on twins give some insight into genetic responsibility for certain outcomes. However, many more studies reveal the consequences of choice.
Research published in 2008 American Society for Clinical Nutrition, examined more than 5,000 pairs of identical and non-identical twin children. The researchers found that genes could explain 77% of the differences in body mass index and waist size of the twins.
In a 2013 study at the University of Helsinki, published in Diabetologia, 16 pairs of identical twins were studied; it was unique because one twin was obese and the other was lean.
This study indicated that while the twins were identical, the obese twin had a poorer blood fat profile, higher liver fat, increased insulin production and resistance, and higher blood pressure.
It is the presence of these conditions that can lead to diabetes, heart problems, and other complications. Unfortunately, being overweight seems to express the genetic predisposition to these illnesses.
The problem with these studies is that they did not explore the effects of exercise on suppressing genetic expression.
Nurture and the environment
Notwithstanding the evidence that genes are responsible for the size of an individual, it cannot explain the increase in obesity over the last 50 years. The human genome does not evolve this quickly.
Our cultural, social, nutritional and physical environment has changed dramatically over this time, and some of the changes include:
- The availability of cheap food 24-hours a day particularly highly processed foods, fast food, and sugar-sweetened drinks
- Relentless marketing campaigns of processed “health” products, diet plans and get slim quick programs.
- Decrease in the physical demands of work, domestic and leisure activities.
- Increase sedentary activities; TV, computers, computer games, etc
It is these dramatic changes in our environment that have thought to have had the greatest impact on our size. However, this “link” is anecdotal, as research cannot confirm that our modern environment is the cause of obesity.
In 2012 a man on death row weighing 204 kg had his sentence commuted to life in prison because he was too large to be humanely put to death. He had been in prison for 27 years and had not lost weight even on rationed prison food.
Fortunately for this man, research into exercise as an effective catalyst for weight loss was only beginning to be seriously explored.
Why do genetically thin people stay thin?
Genetically thin people are not the normal; it is the modern environment that has made it possible for thin people to survive.
The human race has evolved to store fat for times of famine. The more the body experiences starvation, the better it gets at storing any food that it eventually gets.
It is the reason that quick weight loss results in the dieter almost always returning to their pre-diet weight with a little extra weight for prosperity.
The BBC Horizon documentary titled “Why are thin people not fat?” Looked at the obesity problem from a thin person’s perspective.
Professor Fredrik Nystrom (University of Linkoping, Sweden) devised an experiment involving ten naturally thin people. The 10 participants both men and women were to eat double their normal calories to gain 15% of their body weight (average 10kg) in 4 weeks.
The results found that the participants struggled to meet the caloric targets with their normal diet.
The participants had to resort to energy dense processed foods, of chocolate, creams, and/or drinks of high calories to achieve their daily caloric target.
The heaviest participant only managed to gain 5 kgs over the 4 weeks. All participants lost the weight within 4 weeks of returning to their normal diet.
This study replicated a more aggressive experiment conducted in 1967, at Vermont prison where inmates were overfed to achieve 25% increase in body weight, with the purpose of studying the hormonal changes that happen when a person becomes obese.
Despite continual eating, one inmate could not increase this body weight more than 18%, even though his daily calorie intake reached 10,000 calories!
The results of these studies contradict the classical weight management model of calories in, calories out. Particularly as exercise was not allowed during both experiments.
Changing the body’s set point.
Dr. Amanda Sainsbury-Salis of the University of Sydney, is the author of “The Don’t Go Hungry Diet.”
She talks about natural set points where the body feels comfortable at a certain weight. Attempts to reduce this set-point triggers a “famine reaction.”
A famine reaction brings an intense feeling of hunger because of the release of hormones to force the dieter back to their “normal” weight. It is a bit like holding your breath; the body will eventually force you to gasp for air to preserve its life.
Therefore, changing the body’s set point must be done slowly and without feeling hungry. Exercise is the key, and the building of muscle mass unlocks stubborn fat stores.
Exercise gives the body a reason to use energy stores to regenerate and rebuild the body. Muscle mass is a living tissue that releases life-enhancing hormones.
Exercise provides the body with the reason to live and to explore the potential of every day with enthusiasm and vitality.
Whether your psychology is to love or hate exercise is irrelevant to the beating of your heart, without exercise your heart will suffer from the nostalgic memory of times gone by when exercise was playing without exception…
I invite you to join the Shape-Up game and feel the awesome energy of living well.
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I leave you this week with the Portuguese word: Saudade; it means a nostalgic longing to be near again to something that is distant and hopes to be again.
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Exercise and re-experience the love of life irrespective of your body shape.
Live well and eat well.
Anna
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