“I have been speaking to Coca-Cola about using REAL Cane Sugar in Coke in the United States, and they have agreed to do so,” Trump wrote on his social media site.

Some Coca-Cola fans may be rejoicing over the possibility that the iconic soft-drink brand will again sweeten its signature product with cane sugar instead of high-fructose corn syrup.

“Excess consumption of sugar from any source harms health,” said Eva Greenthal, senior policy scientist at the Center for Science in the Public Interest, a nonprofit consumer advocacy group, via emai...