However, in a recent interview with the Otago Daily Times about University of Otago research published yesterday revealing nearly 20% of New Zealand adults had pre-diabetes, Prof Sir Peter Gluckman warned some experts urging the Government to do more were ''cherry-picking'' the evidence.
''I think there is a little bit of patch protection [among experts] going on here.''
Prof Gluckman's advice to target resources as early in life as possible has been used by the Ministry of Health to justify focusing public health programmes on pregnant women and very young children.
Little was known about what worked once people were on the ''pathway'' to obesity and diabetes, whereas prevention was proven, he said.
He was not convinced research from Finland showing the effectiveness of lifestyle intervention in older people would work in New Zealand, which had a different ethnic make-up.
''We've got to be very careful about extrapolating from one population to another. The biology may be quite different, and certainly the risk factors are very different.''
Changing adult lifestyles was complex and hard to sustain.
''We continue to say `diet and exercise' to people who are having a lot of difficulty dieting and exercising. And we have to ask the question `Why are we not succeeding?' And perhaps part of it is for biological reasons.''
Asked about regulatory change, he said there was insufficient evidence about what worked.
''None of us really know how to deal with this problem.''
It was not an ''either/or'' situation. He supported education initiatives and admired the work of University of Otago nutrition and diabetes authority Prof Jim Mann.
''My gut feel is we haven't tackled the problem; there's much more to be done.''
Asked if the Government was spending enough on obesity and diabetes, he said: ''I suspect not.''
His role was to give objective advice in a politically neutral manner, and he was not responsible for the ''trade-offs'' inevitably made by politicians. The research, published in the New Zealand Medical Journal, showed 18.6% of New Zealand adults had pre-diabetes.
Prof Mann, a study co-investigator, said Prof Gluckman was wrong that lifestyle advice could not change behaviour, and there was evidence it worked outside European populations. Prof Gluckman's recommendation to target pregnant women and small children was unproven in a public health context. Ignoring older children and adults risked not dealing with the looming crisis, he said.
Prof Mann said Prof Gluckman was a ''fantastic scientist'' and he would like to collaborate with him on obesity and diabetes.
Prof Mann agreed it was difficult to change behaviour, which underlined the importance of changing the environment through regulation.
