Obesity Flashcards
Overweight and obesity
Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health. A body mass index (BMI) over 25 is considered overweight, and over 30 is obese
Obesity pandemic - reasons
- increased portion sizes
- food abundance / exposure
- rise of convenience food
- Food palatability
- increased use of colours / flavour enhancers
- energy density
- alcohol consumption
- snacking
- speed of eating
How exercise effects the body
Exercise increases cellular A increasing GLUT 4 activation, glucose uptake and mitochondrial activity with enhanced ATP production.
How sleep disruption effects the body
Sleep disruption creates a hormonal imbalance in the body that promotes overeating and weight gain:
- Associated with reduced glucose tolerance and insulin sensitivity
- Disrupts the balance of ghrelin and leptin with increased ghrelin levels promoting hunger and unhealthy food choices.
- Proposed that inflammatory pathways may be activated by insufficient sleep contributing further to obesity.
Sleep hygiene
Epsom salt baths; avoid Blue Light; deal with root cause of sleeplessness; stress management; magnesium and B6; valerian, vervain, chamomile or passionflower teas; Rescue Remedy Night Spray; lighting; natural fibres etc
How Chronobiology effects the body
Chronobiology: Shift work, sleep deprivation and exposure to bright light at night increase the prevalence of adiposity.
- Shift work is associated with obesity, dysregulation of triglycerides and cholesterol, abdominal obesity, T2DM and CV disease.
- Irregular eating patterns are associated with weight gain and obesity. Late-night eating causes higher peak post-prandial glucose levels, reduced lipolysis, circadian rhythm misalignment, together with microbial dysbiosis.
- With clients on night shift try to adhere to a regular eating pattern, whether on day or night shifts. Avoid eating sweets / caffeine on nights as much as possible; look to nourishing snacks
How Processed foods effects the body
Processed foods: Palatability is a key factor in controlling appetite.
- Strong dopamine stimulators (fat, starch, salt, free glutamate, alcohol, caffeine) activate rewarding brain circuits to trigger anticipatory cravings for ‘more’.
- Reward value and palatability of food can override satiety signals. The food industry combine fat, sugar and salt to create a ‘Bliss Point’ to maximise dopamine release.
- Artificially-sweetened drinks have a 47% higher risk of increased BMI. High fructose corn syrup (HFCS) has a strong association with obesity, NAFLD and the metabolic syndrome
Bliss Point = The amount of salt, sugar and fat to maximise deliciousness
How Long-term high cortisol exposure effects the body
- Cortisol levels (overactive HPA axis) are elevated in obese individuals and associated with enhanced abdominal fat deposition.
Factors influencing HPA-axis include high GI consumption, chronic stress, chronic pain, alcohol, chronic sleep deprivation, and night-eating syndrome.
- Stress can alter eating behaviours for 80% of individuals of which 50% consume more food. Stress enhances preference for energy dense ‘comfort foods’.
How Microbiome effects the body
There is mounting evidence for a connection between a disrupted microflora, obesity and diabetes:
- ‘Traditional’ gut flora produces carbohydrate-active enzymes to digest complex polysaccharides as found in plant fibre.
- A by-product is production of SCFAs, used as fuel by intestinal cells.
- The low plant fibre content of an industrialised diet has shifted gut flora towards mucus-utilising bacteria.
- Lack of Akkermansia muciniphilia has been linked with obesity. This can contribute to a damaged mucosal barrier → metabolic endotoxaemia → disrupted insulin signalling and low-grade inflammation.
How Genetic effects the body
Genetic factors play a role in obesity:
- SNPs in the fat mass and obesity-associated (FTO) gene are a strong predictor of obesity.
- VDR SNPs play a role in obesity associated with ongoing inflammation. This may be due to altered gut permeability and microbial translocation.
- Mutations in the ADIPOQ gene are associated with adiponectin deficiency which may predispose to metabolic disruption.
- Polymorphisms in the SLC2A2 gene are associated with increased habitual consumption of sugar and is a predictor of T2DM.
Adipose tissue
Adipose tissue (AT) is a metabolically active organ which regulates whole-body energy homeostasis.
- AT changes in quantity and distribution with age.
- Adipocytes and other cells of adipose tissue produce lipids, steroids, inflammatory cytokines and peptide hormones (e.g., leptin).
- ↑ number and size of adipocytes = WAT expansion = obesity
White adipose tissue (WAT)
Long-term energy storage.
- Subcutaneous adipose tissue (SAT): Situated under the skin.
- Visceral adipose tissue (VAT): Intra-abdominal
With persistent energy surplus, white adipose tissue can continue to grow.
- Chronic energy imbalances with increased storage results in increased adipocyte numbers (hyperplasia) and size (hypertrophy).
- Hypertrophy is strongly associated with dyslipidaemia, IR, T2DM and NAFLD.
- Hyperplasia tends to be associated with fewer serious health effects.
- Consider fasting as a starting point for all obese clients. Research for 800 kcal / day
Brown adipose tissue (BAT)
Abundant in early life.
Beige-white adipose tissue
Similar actions to BAT.
Satiety
Satiety is the physiological state at the end of a meal when further eating is inhibited by ‘fullness’. Many factors are involved in satiety:
- Mechanical stretch of the stomach via the Vagus nerve.
- Adipocyte hormones: Ghrelin, leptin and adiponectin.
- Hormones and peptides: Glucagon-like peptide (GLP-1) and cholecystokinin (CCK).
- Neuropeptides and neurotransmitters: Neuropeptide Y (NPY), agouti-related peptide (AGRP), serotonin.
- Other hormones such as thyroid hormones, oxytocin, cortisol, insulin and glucagon and neurotransmitters (e.g., dopamine and serotonin) also play a role in appetite regulation