Maternal high fat diet (HFD) is a critical factor increasing offspring susceptibility to obesity, yet the impacts of graded levels of dietary fat on this effect have seldom been addressed. Here we assessed the impact of fat levels from 8.3% to 66.6% on offspring adiposity and susceptibility to HFD (41.7%) in Swiss mice.
Lactating mice were fed five diets which varied in fat content from 8.3% to 66.6%, but with constant composition designed to mimic the western diet. Pups were weaned onto a chow diet for 16 weeks. HFD (41.7%) was then introduced to half the male and female offspring for 12 weeks, body weight and food intake was measured every other day. Body fat content was measured every 10 days. Glucose tolerance test was conducted at experimental week 11 as well as the physical activity (PA), respiratory exchange ratio (RER) and energy expenditure (EE) measurement.
Body weight and fat content of the offspring at weaning, 16 weeks later and after both low fat diet (LFD) and HFD exposure were dependent on the maternal diet in lactation. In general, at all time points body weight and adiposity increased in relation to maternal dietary fat content, but the effect was non-linear. Offspring diet also had a major and independent impact. Offspring HFD males and LFD females raised by mothers fed 58.3% fat diet had significantly higher food/energy intake compared to those fed 8.3% fat diet. Maternal 8.3% and 25% fat diets led to the highest PA and RER respectively. Male offspring of mothers fed 8.3% fat diet and female offspring of mothers fed both 8.3% and 25% fat diet had significantly higher EE. Most offspring LFD groups had significantly higher PA, RER and EE than HFD ones. Yet no impaired glucose tolerance on any diet was found in both sexes.
Increasing fat content in the maternal diet during lactation, and HFD in later life, both had significant but independent impacts on obesity. The effect of increasing maternal diet fat content was non-linear.