In 2021, Ludwig et al published a perspective paper called “The carbohydrate-insulin model: a physiological perspective on the obesity pandemic” (Ref 1). I did a Monday note on this paper at the time (Ref 2). In May 2022, Hall et al published a response to the Ludwig et al paper called “The energy balance model of obesity: beyond calories in, calories out” (Ref 3). Ludwig et al have just published their response to Hall et al’s article called “Competing paradigms of obesity pathogenesis: energy balance versus carbohydrate-insulin models” (Ref 4). This could go on for a while.
The ongoing debate is about the cause of obesity. The two positions can be summarised as an energy balance model (abbreviated to EBM) and a carbohydrate-insulin model (abbreviated to CIM). The debate boils down to those who believe that obesity is the result of an energy imbalance – too much energy in and/or too little energy expended – and those who believe what has become known as “the carbohydrate-insulin model of obesity.” The latter can be summarised as the view “that hormonal responses to highly processed carbohydrates shift energy partitioning toward deposition in adipose tissue, leaving fewer calories available for the body’s metabolic needs.”
Last week I summarised the key points from the Hall et al paper. (Look back at the executive summary if you’d like a reminder) (Ref 5). This week we’re looking at the Ludwig et al reply and my views on the exchange.