It doesn’t matter that my thighs are thicker
So is my pubic hair
No one cares that my stomach wobbles
I can still stand strong
Now my happiness shows
Instead of my bones
My eyes aren’t wet with tears
For my skin that is loose and wrinkled
My hips are wider
But so is my smile
My body is full of food
My eyes are full of life
I’m finally living
And it is beautiful
What are the Causes of Obesity?
Portion sizes are now larger and the macronutrient balance of foods has changed with refined carbohydrates /processed foods now making up to 20% of the grocery budget compared to 11% in 1982 and meats declining from 31.3% to 21.5%.
Processed foods are energy dense and nutrient poor and also highly palatable (addictive).
2) Physical Activity:
Changes in our working lives have meant that sedentary employment has become dominant.
There is increased dependence on labour saving devices and services with a resultant drop in energy expenditure.
Exercise has become a leisure activity (often incurring expense) rather than an incidental part of the day.
Increased dependence on motorised transport has further reduced opportunities to exercise.
3) Reduction in Sleep:
Chronic reduction in sleep is a habit that has been developed over the last 2-3 decades and this may play a role in the increased prevalence of obesity.
This is most likely due to dysregulation of glucose metabolism, increased appetite and decreased energy expenditure.
Sleep deprivation may increase catecholamines (dopamine, epinephrine, norepinephrine) and contribute to insulin resistance.
Increased energy intake is caused by abnormal fluctuations in the hormones of appetite.
4) Increased Cognitive Activity and greater mental Stress:
There is a common assumption that stress causes weight loss.
During periods of stress, eating behaviour can change for 80% of people – with half of this 80% eating more and the other half eating less. For the remaining 20%, behaviour remains unchanged.
Overeating is more common in overweight and obese subjects, with under eating more common in normal or underweight subjects.
Those in the upper weight of normal or overweight are more likely to gain weight when stressed.
5) Micronutrient deficiencies:
For centuries, the human race struggled to overcome food scarcity and malnutrition. Surprisingly, malnutrition is at record levels, despite food abundance.
This is most often seen in overweight or obese people, who generally consume vast quantities of energy (calories), but are often found to be undernourished, or suffering from conditions associated with malnourishment. As most of the foods that they consume are generally high in fat & simple carbohydrates and very low in protein, essential fats and micronutrients.
6) Alterations to the human microbiome
In the obese gut, alterations to the balance of bacteria have been found (dysbiosis).
The altered bacterial profile may lead to:
Increased energy harvest via fermentation.
Increased genetic material within the microbiome for carbohydrate and lipid metabolism.
Bacterial endotoxins from gram-negative bacteria can influence host metabolism and inflammation at sites far from the gut.
Knowledge of human gut microbiome interactions is increasing and further research is ongoing in this area.
7) Genetic Factors
Until relatively recently obesity was considered to be an environmental issue which was a result of calorie intake from the diet and the amount of exercise someone is doing. However, this view is quickly changing.
The science shows that our biology, including our genetics, plays an important role in the development of obesity. Many genes have already been identified that play key roles in the development of obesity.
As previously mentioned, globally we have seen almost a doubling in the rates of obesity since 1980. Changes to the genome take thousands of years to become established in a population. Advances in the study of genetics and epigenetics are showing how our genes influence everything from our physiology to our psychology, and vice versa, not only long-term but also over the very short term.
What is Leptin?
A satiety hormone, regulates appetite and energy balance of the body.
Produced by fat cells when they are ‘full’ of tri-acyl-glycerides (TAG)
Acts as a signalling factor from fat tissue to the central nervous system (brain), regulating food intake and energy expenditure.
It is hypothesised that via this leptin feedback loop, homeostasis of body weight and a constant amount of body fat are achieved.
Leptin causes decreased hunger, increased activity and increased thermogenesis.
What is Leptin Resistance?
Desensitisation for the leptin signal is referred to as leptin resistance. Defective appetite control in obesity is associated with leptin resistance.
Peripheral Leptin Resistance:
Leptin can modify insulin sensitivity, tissue metabolism, stress responses, and reproductive function.
Overtime, these changes in metabolism produce abdominal weight gain in both genders, as well as thigh and hip weight gain in females, chronic fatigue, sleep problems, cardiovascular distress, and a host of other changes.
Additional fat tissue then contributes further to leptin resistance, creating a viscious cycle.
Eating disorders are 15th among top 20 causes of disability in women.
In the UK 11,0000 people are diagnosed annually with anorexia or bulimia nervosa.
Average duration of recovery is 5-6 years.
What causes Anorexia?
The cause of anorexia nervosa is complex and multifactorial.
Risk factors include:
1) A perceived lack of control over life or situations.
2) Dysfunctional families and traumatic experiences in childhood.
3) Positive reinforcement that fatness makes you unlovable (media and social pressures).
4) Nutritional deficiencies.
5) Menarche (onset of menstruation) - there are theories that the hormonal and bodily changes involved with the onset of 6) puberty can start the process.
Early signs of Anorexia:
There is often an increased incidence of exercise (normally in secre).
There is also an increase in weighing themselves a few times a day.
Food may be counted out, measured or weighed.
Development of the disorder:
When the body is starving, the brain undergoes biochemical changes which disallows rational thought processes, hence making the disorder a downward spiral.
The main disturbances include:
Acute tryptophan depletion
Biochemistry of Starvation:
1) The glycogen storage is used up, the level of insulin in the circulation is low and the level of glucagon is very high.
2) Muscle tissue is broken down to provide substrates for gluconeogenesis (synthesis of glucose) to maintain blood sugar levels.
3) The primary energy source is fats.
4) The liver coverts fatty acids into ketone bodies which can be detected in a urine test.
5) The brain starts to use ketone bodies as a source of energy (due to a lack of glucose).
Zinc is the most crucial nutrient deficiency in anorexia. The symptoms and risk factors for anorexia and zinc deficiency are the same!
Risk Factors for Anorexia and Zinc Deficiency:
Female under 25
Symptoms for Anorexia and Zinc Deficiency:
Loss of appetite
Amenorrhoea (absence of periods)
Impotence in males