SPEECH

I did epidemiology of obesity and the right approaches to combatting the disorder. Thought epidemiology was the appropriate term because it refers to the study of a disease and all

the factors that play a role in its frequency and distribution. From those relationships, the causes and means of prevention can hopefully be determined. It’s a scientific basis for evidence-based medicine. So not only the treatment of a condition but also prevention - which I think is really important and what I wanted my whole inquiry to be focused on.

Most, articles, discussions, papers, and even speeches on the topic of obesity all start off (in my opinion) in more or less the same way in that Obesity is a global epidemic with reference to some scary prevalent statistic.

what is the general view on what causes someone to become fat? Why does somebody gain weight, what do they do, what do they not do?

= eating too much, not exercising enough, eating the wrong foods we eat food = fuel, our energy source- and exercise/physical activity is expending that energy visual terms: E stored = E in – E out

established conventional view/commonsense understanding of causes obesity

an imbalance in this equation (energy), with it being applied to a biological system over a certain time period.

justified by the first law of thermodynamics; effectively the law of conservation of energy (E). broadly correct, not what should be critiqued.

However another justification of this belief is (EIN) and (EOUT) are exogenous variables and (Estorage) is a fully endogenous variable (internal variable- within us).

could roughly be stated then: that (EIN) and (EOUT) are independent variables and weight gain is dependent variable.

implies right-hand side equation (calories in–calories out) causes left-hand side (weight gain).

But there is no causality embedded into the first law of thermodynamics.

There is no theoretical reason why causality may not operate in the reverse direction; that is, weight gain may, via homeostatic mechanisms, regulate (EIN) and (EOUT)

In order for us to maintain our (ESTOR) we would have to assume that we can independently balance our energy consumption and our energy expenditure to be within 99 % of each other = unreasonable assumption.

homeostatic mechanisms that influence the consumption of calories and the body’s energy expenditure making these variables partly endogenous and influenced by weight gain.

There are such mechanisms; an example is leptin. hormone produced adipocytes tells brain we have enough energy storage, our satiety hormone; this is what decreases our appetite and reduces our energy expenditure.

that means that if a person gains weight, this will lead to higher leptin levels, which will reduce appetite and an increase in energy expenditure leading to weight loss.

If this leptin mechanism works correctly, a reverse causality has been introduced into the energy imbalance equation (from the LHS to the RHS) and so the conventional energy imbalance view of obesity loses its theoretical justification.

it doesn’t make any sense b/c if we look around and see that over 600 mil ppl are obese and that ppl are dying more of under nutrition than over nutrition,.

After leptin was discovered, so was “leptin resistance”, which is very similar to insulin resistance –high levels of something are resulting in a dysfunction with the mechanism. Understanding the causes of Leptin resistance is one of the holy grails of obesity research.

There are numerous factors that directly disrupt the mechanisms and the causal interactions between them are highly complex with a myriad of variables. It’s not yet fully understood but what is understood is that in obese individuals a major homeostatic mechanism is disrupted.

The common energy imbalance view of obesity has clear and pretty logical intervention strategies to combat obesity: if obesity is caused by taking in more calories than are being burnt over the long term, then the strategy would be to just eat less and exercise more.

it should be understood that this logic is flawed because (EIN) and (EOUT) are not exogenous variables. They are partly endogenous.

crucial is that there is a paradigm shift in understanding the causes of obesity. need to move towards the view that obesity is a metabolic and hormonal disorder. B/c once we do that, we can establish effective interventional strategies that focus not on just an energy imbalance but on underlying dysfunctions. For example, exercise may be an essential intervention not simply because it burns calories but because it can improve insulin sensitivity and help to normalize stress hormones. It is crucial that there is a paradigm shift because it will move the basis of current interventional strategies from trying to influence human agency – fighting gluttony and laziness – to actually trying to influence human biology in the face of an obesogenic environment.

This is pivotal to the combat of obesity.