SUGAR, HOW YOU GET SO FLY?

Damon Gameau (“Sweet spot”, January 20) is an excellent film-maker and communicator and his 2015 documentary That Sugar Film has really helped to bring the health dangers of sugar to the public.

However, during the 60-day high-sugar diet that saw his weight go from 75kg to 84.5kg, he still had to obey the first law of thermodynamics: energy cannot be created or destroyed. It is therefore impossible that his energy intake remained stable at 2300 calories a day and his physical activity did not change.

The Body Weight Planner from the US National Institutes of Health back-calculates the calories needed to achieve this weight gain based on robust physiological evidence. To achieve that large weight increase so quickly, Gameau would have had to consume about 40% more energy (over 1000kcal/day more), and to maintain his higher weight over the long term, if he had wanted to do that, would have required an extra 8% more energy (about 200kcal/day) more than his baseline intake.

So, why the discrepancy with Gameau’s calorie figures? The answer is that self-estimates of energy intake are notoriously wrong. Even under ideal research conditions, people usually under-report energy intakes by 20-30% – it’s just too hard to be accurate.

The idea that sugar has particular properties that allow weight gain without a higher calorie intake is a myth that needs to be busted. The idea that it has properties that increase weight by making it easier to consume more calories and that it increases blood triglyceride levels, fatty deposits in the liver and dental caries is the important message. Boyd Swinburn University of Auckland school of population health

Who is the me that my brain is tricking into wanting to eat sugar? My whole body is me, including my brain. I am writing this letter, or is it just my fingers typing while “the me” that is irritated by the idea of a “disembodied me” sits back and watches? No, it can’t be – my eyes are involved and my heart and my postural muscles and my kidneys.

So an article that has many facts about how we respond to refined sugar is undermined by continuing to perpetuate the notion that our physiology functions as separate units that somehow feed into an invisible me. Our living bodies are us. I go to a movie and it is not by accident that my body goes too. Bruce Ross (Narrow Neck, Auckland)