January 15, 2020
2 min read

‘Metabolic flexibility’ reduced during pregnancy for women with overweight or obesity

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Rachel A. Tinius

Lipid oxidation rate an indicator of “metabolic flexibility” may be greater among women with normal weight vs. women with overweight or obesity during pregnancy, according to findings published in Metabolism. In addition, insulin resistance and inflammation may be influenced by this flexibility.

“So many women are starting pregnancy obese and overweight, which puts both mom and baby potentially at risk. Understanding the mechanisms that underlie poorer outcomes may provide opportunities to design more targeted interventions,” Rachel A. Tinius, PhD, assistant professor of exercise science at Western Kentucky University School of Kinesiology, Recreation and Sport in Bowling Green, told Healio. “Given the abundance of unhealthy, high-fat meals Americans eat, it is really important that we understand what happens to these dietary fats during pregnancy. They could be stored, thus, causing weight gain, used for energy or even passed to the baby; all of which have downstream implications.”

Tinius and colleagues evaluated lipid oxidation rate, insulin resistance and high-sensitivity C-reactive protein — a marker of inflammation — among 29 women with a BMI of more than 25 kg/m2 or overweight/obesity before pregnancy (mean age, 30 years) and 35 women with a BMI between 18.5 kg/m2 and 24.9 kg/m2 or normal weight before pregnancy (mean age, 29.8 years). The researchers made these comparisons based on measurements taken at baseline, 2 hours and 4 hours after a 1,062 kcal meal (55.93% fat) during a laboratory visit 32 to 38 weeks into pregnancy.

Pregnant woman and doctor (Shutterstock) 
Lipid oxidation rate — an indicator of “metabolic flexibility” — may be greater among women with normal weight vs. women with overweight or obesity during pregnancy.
Source: Shutterstock

Lipid oxidation rate rose by 29.3% among women with overweight or obesity at 4 hours and by 48% among women with normal weight (P = .035). The researchers also observed a negative correlation between insulin resistance following the meal and lipid oxidation rate at 2 hours (P = .016) and at 4 hours (P = .019). In addition, women with overweight or obesity had greater levels of C-reactive protein at 4 hours than those with normal weight, according to the researchers, who further noted that for women with overweight or obesity, C-reactive protein variation and metabolic flexibility at 4 hours were inversely related.

“Overweight and obese women metabolize fats differently than lean women, and this could be a reason why many of them see poorer pregnancy outcomes,” Tinius said. “We hope this information can be used to design future clinical trials. The study findings suggest that overweight and obese pregnant women need to be careful about eating excessive dietary fats as they may be less able to metabolize them appropriately, which may contribute to inflammation and/or insulin resistance.” – by Phil Neuffer

For more information:

Rachel A. Tinius, PhD, can be reached at rachel.tinius@wku.edu.

Disclosures: The authors report no relevant financial disclosures.