The Sugar Diet

Sugar being processed at the Louisiana Sugar Cooperative mill in St. Martinville, La.

"The third shift that underpinned Britain's Industrial Revolution was a far greater reliance on food imports. Just as it used coal from underground to power its new steam engines, Britain used food from overseas to provide energy for its workers. From its possessions in the West Indies, it brought in vast quantities of sugar, which provided an astonishing proportion of Britain's caloric intake during the nineteenth century, increasing from 4 percent of all calories consumed in 1800 to 22 percent by 1900."
- Tom Standage, An Edible History Of Humanity

That is astonishing. For a person consuming about 2000 calories a day:

• 4% is 80 calories, between 5 and 6 teaspoons of sugar a day.
• 22% is 440 calories, between 29 and 30 teaspoons/day.

The sugar was used either to sweeten tea (another import), or to make jam, which was eaten on bread throughout the day. I'm not sure if those figures accounted for rum (another sugar derivative) consumption.

If a high-carb diet causes weight gain (Gary Taubes in his book Good Calories, Bad Calories said, "Carbohydrates make us fat and ultimately cause obesity."), why didn't the potato-sugar-wheat diet in the UK in the 19th century lead to obesity?

For comparison, the USDA lists US refined cane and beet sugar consumption in 2009 at 13.4 teaspoons/day, down from 21.4 teaspoons in 1970. (Although we've found other ways to sweeten our tea.)
________ Photo from New York Times, Seeing Sugar's Future In Fuel. Caption: "Sugar being processed at the Louisiana Sugar Cooperative mill in St. Martinville, La."