A Harvard-led study suggests that avoiding low-quality carbohydrates like refined grains and starchy vegetables may help prevent middle-age weight gain, based on tracking over 136,000 adults for up to 28 years. Increased consumption of low-quality carbohydrates was linked to gaining up to three pounds every four years, while adding fiber to the diet was associated with gaining 1.7 fewer pounds over the same period, with refined carbohydrates like white pasta and bread highlighted as significant contributors to weight gain. 

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