Throughout life, the body weight in humans varies within a very narrow range. This is despite the large day-to-day fluctuations of food intake – and the energy expenditure adjustments to this energy intake. Thanks to this mechanism, the energy balance remains stable over long periods of time.
It has been suggested that individuals have a predefined energy store status, called body weight set point.
This is determined by the combination of environmental and genetic factors. Any attempt to move away from the body weight set point remains vain. This explains why it’s so difficult to maintain desirable weight after dieting… and why the body kicks back into predefined energy store status.
The existence of this regulatory system implies a permanent and complex dialogue between the brain, the peripheral tissues from adipose tissues – and the pancreas, liver and muscles.
Reproductive hormones have also been considered as adiposity signals, which further complicate regulatory mechanisms for weight homeostasis.
Growing knowledge of adipose tissue biology – as well as the possibility of studying gene expression on a large scale in human adipose tissue, has offered a new approach in achieving long-term control of body weight through Genetic Testing.
Genetic testing for weight loss examines and identifies different metabolic pathways and physiological parameters – as well as the disturbances which are responsible for the development of overweight or obesity.
The lipid metabolism refers to the processes that lead to the creation and degradation of lipids in the human body. Fatty acids play an important role in the cell structure since they are components of the cell membrane. Lipids (mainly in the form of triglycerides) are the body’s principal form of stored energy. Lipid metabolism requires a balance between degradation (lipolysis) and synthesis (lipogenesis) according to the energy need of the organism. Presence of certain genes (for example FABP2) increase fatty acid uptake, leading to easier weight gain than in individuals who do not have this gene.
Adipogenesis (not to be confused with lipogenesis) is the cellular process during which pre-dipocytes differentiate into mature fat cells. Mature adipocytes control the insulin signalling cascade, thus modulating insulin sensitivity. In addition, adipose tissue produces several cytokines that regulate energy homeostasis, lipid and glucose metabolism. Presence of the PPR genetic variation increases insulin sensitivity, allowing better glucose utilization as opposed to the ones who do not have it. Therefore, they have to be on a permanent low GL food in order to keep that weight off.
Anthropometry refers to certain characteristics such as body weight, height or circumference. The genes regrouped in this section are involved in various metabolic pathways, and are associated with anthropometric measures. Presence of some genetic variations like APOA5 leads to increased BMI. Unfortunately, the body will try to keep this increased BMI as soon as the diet has stopped.
Being overweight and obesity are associated with chronic low-level inflammation in adipose tissue. The morphological changes in adipose tissue associated with obesity trigger the excessive secretion of a wide variety of pro-inflammatory mediators. An elevated inflammatory status of the adipose tissue may lead to atherosclerosis or liver steatosis, which further enhances weight gain. Presence of TNF-alfa genetic variation can lead to increased insulin resistance – as well as a resistance to lose weight.
When the food we consume reacts with oxygen, energy is released through cellular respiration. The human body uses this energy for a wide range of purposes, with the major part being used for the basal metabolic requirements. As our muscles are not perfectly efficient in converting chemical energy into work, they also create heat. This step is called thermogenesis – a process that involves beta adrenergic receptors that bind catecholamines (the hormones that prepare the body for physical activity).
Presence of ADRR1 gene decreases the response to exercise – which explains why some people don’t really lose weight with exercise, while others lose a substantial amount with increased energy expenditure and intensive gym activity.
The appetite control system serves to regulate the adequate energy intake to meet the body’s metabolic needs. This process needs the coordination between the digestive tract, the adipose tissue and the brain. It implicates the action of different hormones such as ghrelin (the ‘appetite hormone’) and leptin (the ‘satiety hormone).
A decreased response to satiety or an increased sensitivity to hunger may lead to excessive food intake. An example is when the LEPR variation is positive – in which case there will be a decrease in leptin sensitivity and decreased satiety. Genetic variation can influence weight control to such a degree that a person will not be able to achieve long term weight control…unless personalised treatments according to genetic variation takes place.
Therefore it’s highly beneficial to use genetic testing for personalized eating plans for life. A specific diet with adaptogens that targets each genetic variation should be prescribed for long term results.
Genetic testing for weight loss is available at 8th Sense Sandton – www.8thsense.co.za