That Sugar Film is a 2014 Australian documentary starring and directed by Damon Gameau. The film looks at hidden sugar in foods and the effect it can have on the human body.
The film follows Gameau's experiment on himself, changing from his normal diet containing no refined sugar, to a 'health-conscious' diet low in fat but high in sugar, equivalent to 200 grams (40 tsp) of sugar per day. As a result, Gameau gained weight, grew lethargic, and developed fatty liver disease. The sugar diet was selected such that his calorie intake was not increased from his normal diet.
Interviews with experts attribute this change to the high level of sugar he is ingesting, and in particular suggest that fructose may be the main culprit. It is suggested that artificial sweeteners may be no better.
The viewers are introduced to the "bliss point", a term coined in the 1960s which applies here to the amount of sugar you can add to a food to make it optimally desirable. Adding more sugar beyond the "bliss point" leads to significant drop in desirability.
Following the experiment, he returned to his previous diet, and the ill effects are largely and quickly reversed.