Childhood obesity is reaching alarming proportions in many countries and poses an urgent challenge to healthcare systems. It affects a child’s immediate health and quality of life, and children with obesity are five times more likely to remain obese as adults compared with those without childhood obesity. Preventing childhood obesity is not just a medical concern, as it represents the largest contributor to the overall healthcare costs. Mothers’ pre-pregnancy body mass index (BMI) is a strong risk factor for childhood obesity, accounting for over 20% of childhood obesity cases, indicating a strong mother-to-child transmission. While genetics play a role, environmental factors during pregnancy and early life are also important. The period from conception to age two—“the first 1000 days”—is the most critical for developing obesity-related disorders. Data from human cohorts indicate that faster weight gain in the first 3 months of life is associated with a higher body fat percentage and a greater degree of abdominal obesity in childhood and later in life.
Breastfeeding is a recognized protective factor against obesity, offering nutritional and immunological advantages. Breastfed infants have a lower risk of becoming overweight than formula-fed ones. The ExMilk project is based on the premise that breastmilk is nutritionally optimal, even for infants of women with overweight or obesity. However, recent evidence shows that breastmilk composition differs between mothers with high and low BMI. ExMilk aims to improve breastmilk composition in women with overweight or obesity.
Maternal obesity is associated with changes in breastmilk components linked to childhood obesity risk, suggesting certain milk molecules mediate obesity transmission. The interaction between maternal lifestyle, breastmilk composition, and infant health is an emerging research field, with known influences from smoking, BMI, gestational diabetes, and diet. Yet, there is no experimental evidence that lifestyle-induced changes in breastmilk affect infant obesity risk. Exercise, a key behavioral factor influencing metabolic health, remains largely unexplored in this context. The ExMilk project will determine how exercise during lactation affects breastmilk composition and, consequently, infant obesity risk.
This interdisciplinary project investigates both acute and long-term exercise effects on a wide range of breastmilk components in women with overweight/obesity. By linking breastmilk data to comprehensive data for the infants, we aim to identify mechanisms through which maternal exercise influences infant obesity risk. To reach our goals, we will perform gold-standard randomised trials and analyse biological samples from mothers and infants on several analytical platforms. Our interdisciplinary expertise will enable us to break new ground in understanding how exercise during lactation modifies infant obesity risk.
