So-called pear-shaped women with wider hips and a smaller waist have been found to give birth to children who have, on average, higher test scores. According to a 2008 American study published in Evolution and Human Behavior, lower hip-to-waist ratio and higher amounts of buttocks and thigh fat were found to be indicators of intelligence—now we are finally beginning to understand why.

In a more recent, follow-up study, co-author Steven Gaulin, PhD, Professor of Anthropology at UCSB and his team recently discovered that mothers with healthy stores of gluteofemoral (thigh and buttock) fat had higher amounts of long-chain omega-3 fatty acids known as docosahexaenoic acid (DHA) in their blood lipid profile and breast milk. DHA comprises 20% of the brain’s structure, including all cell membranes. Unsurprisingly, breast milk with the highest levels of DHA correlated directly with children’s higher test scores—an even better predictor than money spent on education per student. Conversely, high levels of another fatty acid, omega-6 (linoleic acid), in breast milk predicted lower test scores.

To understand this booty-to-booby fatty acid connection, Gaulin explains to LivingHealthy that women’s bodies evolved to store precious DHA in gluteofemoral fat for future offspring nourishment. Even if you choose never to spawn, you’re stuck with this evolutionarily determined deposit of fat.

According to Gaulin, a mother’s DHA stores are crucial to her child’s healthy brain development in utero and during the first couple years of life. “DHA is concentrated in the growth cone of each nerve cell as it is growing, reaching out and making connections,” he explains. “Not only is DHA crucial to growing a brain, but it’s critical in its day-to-day functioning. Neurons won’t fire without DHA.” Gaulin also notes that during pregnancy about 80% of fetal brain development pulls from a mother’s gluteofemoral fat deposits, and roughly 60-80% of the DHA in breast milk is sourced from the same part of the body—reserves that are developed while the mother is still in utero herself! A long-term omega-3-rich diet, meanwhile, will help to create stores of DHA in other depots in the body, and can help supply the remaining DHA in breast milk production.

Complicated, right? While these studies suggest that eating a diet rich in omega-3s during pregnancy and lactation has a limited effect on growing a baby’s brain and its massive amount of neural connections, diet still is key in supplying the mother’s needs for DHA for her own brain. Meaning, for both baby and mother, says Gaulin, “The brain you do have will work better if you give it enough DHA.”

But remember the omega-6 that tanked test scores? Turns out, omega-6 consumption is extremely high in the typical Western diet, and those omega-6s block the pathways and receptors where helpful omega-3 molecules work, says Gaulin. To balance omegas in the diet, Karen Peters, RD, IBCLC, retired Executive Director of BreastfeedLA, recommends reading food labels and avoiding the big omega-6 culprits: processed corn, soybean, sunflower, safflower and other vegetable oils. She also tells LivingHealthy that we should be eating more contaminant-free, omega-3-rich fatty fish such as wild-caught salmon, anchovies and sardines (algae, seaweed and krill are vegan options). Peters notes that the FDA and EPA recently recommended eating 12 ounces of fatty fish per week.

If you’re interested in supplementation, Peters shares La Leche League’s recommendation for fish oil, or algae/krill capsules: 200-400mg a day for pregnant and lactating women, since too much DHA can interfere with blood clotting. Gaulin suggests 1,000mg daily for all adults (although both Peters and Gaulin acknowledge that the FDA’s Generally Regarded as Safe amount is 3,000mg a day).


  1. Evolution and Human Behavior
  2. UCSB News
  3. FDA
  4. La Leche League