Why alternative diets like fasting, low carbs, don't work: Hong Kong nutritionists

South China Morning Post

18-05-2025

The effectiveness of intermittent fasting, low-carbohydrate meals and other alternative diets to lose weight is not backed by enough scientific evidence and could backfire, Hong Kong nutritionists have warned after conducting a survey that showed 40 per cent of respondents had tried such methods.
The Hong Kong Nutrition Association revealed on Sunday findings of a survey it conducted between March and the beginning of May, in which 364 respondents, or about 40 per cent of the 916 in total, had attempted at least one of a variety of dieting methods.
It added that the residents polled obtained dietary information from possibly unreliable sources, with more than half accessing unverified sources from social media, and over four in 10 from friends and family.
Among respondents who went on diets, 51 per cent had tried intermittent fasting, which involves eating once in eight hours and fasting for the remaining 16 hours, while 43 per cent had gone on diets with a low level of carbohydrates.
Weight control and improving their health were the key reasons for going on diets, as indicated by 76 per cent and 56 per cent of respondents, respectively.
But the association said the effectiveness of such diets was not backed by sufficient scientific research and could lead to adverse health effects.
'Refraining from consuming carbohydrates can slow down metabolism rate, worsen memory, [cause] low energy, low blood sugar and low spirit,' Leona Leung Yuen-ling, the association's vice-president, said.