A new Singapore study suggests that pregnant women who consume more of their daily food intake after 7 pm, and who consume lower quality diets during pregnancy, are three times more likely to experience a postpartum weight retention of 11 pounds (5 kilograms) or more, 18 months after giving birth.
The research is published in the journal Nutrients.
Retaining more weight after the first year of giving birth is associated with a higher body mass index (BMI) even at 15 years postpartum. Post-pregnancy weight gain also appears to be more harmful than weight gain in other stages of life as the retained body fat is typically deposited in the abdomen (visceral fat) rather than in other parts of the body.
This phenomenon has a profound effect not only on the mother’s lifelong health including metabolic and cardiovascular disease consequences, but also on subsequent pregnancies and the future health of her child.
For the study, researchers from KK Women’s and Children’s Hospital (KKH) in Singapore drew data from a large scale birth cohort study, GUSTO (Growing Up in Singapore Towards healthy Outcomes).
“Our research, based on multi-ethnic Asian women, shows that although predominantly night eating and lower diet quality have been independently linked with weight gain, practising night eating along with low diet quality demonstrated the greatest likelihood of substantial postpartum weight gain and retention even after 18 months,” said lead author Dr. Loy See Ling from the department of reproductive medicine at KKH.
Overall, 16 percent of the 687 pregnant women involved in the study gained and retained five kilograms (11 pounds) or more at 18 months after giving birth.
The researchers found a stronger likelihood of postpartum weight retention when predominantly night eating was practiced together with a higher diet quality; whereas those practicing predominantly day eating with lower diet quality showed a weaker association with postpartum weight retention.
Therefore, night eating may be more damaging than a lower-quality diet in contributing to substantial postpartum weight retention.
“Our body systems have evolved to metabolise food during the day and rest during the night,” said co-author Associate Professor Fabian Yap, from the endocrinology service, department of paediatrics at KKH.
“Hence, consuming more calories at night than day mismatches our body’s natural body time clock by disrupting the metabolic rhythm in various organs such as liver, stomach, pancreas, fat tissue, resulting in disruption of energy metabolism. The consumption of more calories at night is also closely linked with a later bedtime and hence, associated with overweightness and obesity.”
This finding needs further investigation and confirmation due to the modest number of women within the group of night eating with higher diet quality.