As I dietitian, I have had a few people ask me about “That Sugar Film” and the findings of the film. If you have not seen it, the film is based on an actor’s experiment where he exposes himself to the amount of sugar that is in the standard Australian diet.
I enjoyed the film, it highlights some of the major issues of eating a diet high in added sugar – that is, any sugar that is added by the manufacturer or us at home. This includes fruit juice but excludes whole, fresh fruit.
As with most documentaries of this type, following one person on a singular journey does not make for good science – but it does put a face to a story and help explain things that can happen within the body. This movie uses great images and explains the mechanics of the human body quite well and is mostly on point.
My biggest issue with the film is that it appears to be based on a highly inflated “standard Australian diet” with 40 of teaspoons of sugar a day. This is a massive amount of sugar. I looked into South African numbers and found studies that give a range of added sugars between 32-81g of sugar per day (4-20 teaspoons per day).*
I was not at all surprised that Damon (the actor) gained weight and felt terrible – anyone eating that amount of highly refined carbohydrates is going to be on a blood sugar roller coaster. He had to replace a large amount of nutritious food (like vegetables) with less nutritious food (like sweetened cereals) in order to eat the full amount of sugar required. Secondly,I also found the total amount of energy he reported for his usual diet high considering the amount of fat he was eating. Most people on a diet as low in carbohydrates as his, tend to experience a drop in appetite as a result of producing ketones (burning fat). Self-recording nutrition intake is known to be difficult to accurately record and I think his efforts may be over-inflated.
In summary, the assumptions of the movie – from which some of his conclusions are drawn – do not sit well with me. In South Africa, the average sugar intake is higher than the new limit proposed by the World Health Organization in 2015: less than 10% of energy from added sugar or no more than 25g of sugar per day. While I question the assumptions of the film, such as the 40 teaspoons of added sugars daily, I agree with the basic message that we should steer clear of sugary, ultra-processed foods and focus on eating a balanced diet based on plant foods, heart healthy fats and unprocessed proteins-rich foods.
*Mchiza ZJ, Steyn NP, Hill J, Kruger A, Schonefeldt H, Nel J et al. A review of dietary surveys in the adult South African population from 2000 to 2015. Nutrients 2015, 7, 8227-8250; doi:10.3390/nu7095389