Changes in Multiple Dietary Factors Lead to Long Term Weight Gain: Harvard School of Public Health

A series of three separate studies were conducted on how changes in the multiple dietary factors and other lifestyle factors relate to long term weight gain. The report gave stunning results and based on them the researchers even gave some suggestions to overcome that condition. Lets look in to the story in detail.

According to the research conducted by Harvard School of Public Health (HSPH), modest changes in specific foods and beverages, physical activity, TV watching, and sleep duration were strongly linked to long term weight gain. In particular, changes in the diet had the greater impact on weight gain.

About the research

As mentioned earlier the research was carried out in a series of three different studies which evaluated the changes in multiple specific lifestyle factors and weight gain for every four years by a continuous follow up for 12 to 20 years. The final analysis included 50,422 women in first study called NHS (the Nurses’ Health Study), 47,898 women in NHS 2 (Nurses’ Health Study II), and 22,557 men in HPFS (the Health Professionals Follow-up Study), all of whom were free of obesity or any chronic disorders at the beginning of the study.

Research Report

The study showed that all the participants gained an average of 1.52 kgs during every four year period, which corresponded to a weight gain of 7.64 kgs over a period of 20 years. When the relationship of lifestyle changes with weight gain were evaluated, the findings were quiet similar in all the three studies.

The foods associated with the greatest weight gain over the period of 20 year study period included

  • potato chips(for each one increased daily serving,+0.77kg more weight gain in every 4 years)
  • other potato dishes and items (+0.58 kg)
  • Sugar sweetened beverages (+0.45 kg)
  • Unprocessed meats (+0.43 kg)
  • Processed meat (+0.42 kg)

In contrast, foods associated with less weight gain when their consumption was increased are

  • Vegetables (-0.1 kg)
  • Whole grains (-0.17 kg)
  • Fruits (-0.22 kg)
  • Nuts (-0.26 kg)
  • Yogurt (-0.37 kg)

The research also showed that the changes in the physical activity and TV viewing do have some influence on weight gain. Moreover, those who slept 6-8 hours a night gained less weight when compared to people who sleep less than 6 hours and more than 8 hours.


The researchers suggested that focusing on total calories we are consuming and checking the total fat content, energy density, or the percentage of sugars may not be useful for controlling the intake and sometimes it is also misleading. Instead they found that eating more healthy foods, focusing on overall dietary quality would be more beneficial.

The most useful dietary metrics for preventing long term weight gain appeared to be:

  • Consuming less liquid sugars like sodas. Fewer sweets and avoiding starches like potatoes. Minimizing Refined grains like white bread, white rice, cereals low in fiber, and other refined carbohydrates.
  • It is good to take minimally processed foods like fruits, vegetables, whole grains, nuts and yogurt and fewer highly processed foods like white breads, processed meats, and sugary beverages.

These kind of healthy changes in your dietary pattern and lifestyle can curb the long term weight gain in many ways by influencing biological processes such as changing hunger, insulin levels, reducing fats, etc.

Finally, the bottom line of this report is to make wise food choices and adopt a healthy lifestyle which includes increase in physical activity, adequate sleeping habits and decrease in the regular TV watching.

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