How many teaspoons of sugar in boiled yam?

White yam is a starchy tuber of the Dioscorea family and a staple across West Africa and the Caribbean. It is not related to the orange-fleshed sweet potato sold as “yam” in North America. White yam has rough, bark-like brown skin and firm white flesh, and in Nigeria and Ghana it is boiled, fried, roasted or pounded.

The African and Caribbean foods chart, credited to Dr David Unwin and Dr Geoffrey Livesey, lists boiled white yam at a 150g serving. That chart prints a serve size and a teaspoon figure for each food and nothing else: no glycaemic index and no glycaemic load. So no GI or carbohydrate weight is shown on this page, and the load was back-calculated from the teaspoon figure.

The chart’s eleven rows run from boiled staples to dry flours and fufu doughs, and end with okra and eggs.

Yam varieties are distinct species. White yam, yellow yam and water yam differ in texture, moisture and flavour, and the chart specifies white yam only.

Yam is harvested once a year, and new yam festivals marking the harvest are held in parts of Nigeria and Ghana. Pounded yam, a smooth dough made by pounding boiled yam, is eaten widely in West Africa but has no row on the chart.

Yam flour, which is used to make the dough known as amala, is on the chart and has its own page.