Sir: If we are to make any progress in our understanding of the relationship between diet and health, it is essential to address the key issues honestly and openly. Unfortunately, the debate on sugar has been characterised by misrepresentation of the evidence on all sides.

Mark Carr, group chief executive of AB Sugar, stated in The Saturday Essay (25 January): “Government statistics show there has actually been a reduction of almost 12% in total sugars consumption over the past decade, so the suggestion that an increase in obesity results only from sugar consumption is not supported by the data.”

But the big rise in obesity occurred before this. From 1950 to 2000, sugar intake more than doubled from c30kg to 70kg/year, much of this due to the fivefold increase in soft drink consumption from 1975 to 2000.

Dr Ian Campbell, in the Third Party (also 25 January), said: “There is no clear evidence that sugar is directly implicated in causing type 2 diabetes.”

This statement beggars belief. Type 2 diabetes is caused by excessive glucose in the blood, which is directly related to the amount of sugar and refined carbs in the diet. The reality is that the incidence of diabetes has doubled in the last 15 years.

Thousands have lost weight and overcome diabetes by lowering their intake of sugar. Even more convincing are those cancer patients who have recovered by eliminating sugar from their diet after German scientist Otto Warburg discovered that cancer cells can only survive with sugar as their source of energy!

Verner Wheelock, Verner Wheelock Associates