Prof Weiner is visiting the University of Otago for three weeks as a William Evans Fellow.
He told the Otago Daily Times this week obesity, and the resulting diabetes type 2, presented a "huge" challenge for Western countries.
He said he did not know the answer to stopping people from eating too much.
Many of his patients were obese, and it was very difficult for them to get their eating under control.
Prof Weiner said kidney failure was now a less common complication of diabetes. However, as the incidence of type 2 diabetes was ballooning, demand was still growing for dialysis.
Dialysis, for "historical" reasons, was funded by the US Government, meaning patients with no medical insurance were not at a disadvantage.
This made it a big cost for the Government, which looked for ways to reduce spending.
United States patients tended to have dialysis in medical clinics, in contrast to New Zealand where it was predominantly a home-based service.
This was an area in which the US could learn from New Zealand in encouraging home-based delivery, he suggested.
Prof Weiner is based at the University of Florida and his research interest centres on renal acids, the role and behaviour of which traditionally had not been well understood.
New thinking had been developed in the past five years which altered how certain diseases associated with kidney function and body acid were viewed.
"We've completely reversed our understanding of some things," he said, which was "unusual" for medicine.
Prof Weiner, also a practising clinician, was recently recognised by US News as one of the top 1% of nephrologists in the US.
This week, he will address a research meeting of Australian and New Zealand renal scientists in Queenstown.
