New Research:  Can Obesity Be Passed Down from Parents?

A recent study indicates that the likelihood of experiencing obesity in middle age is linked to whether one’s parents had obesity at the same stage of life.

Conducted in Norway across multiple generations, the research revealed that individuals were six times more likely to have obesity in middle age if both of their parents were obese during that period.

Even if only one parent had obesity during middle age, the risk of obesity was still more than three times higher.

Obesity, Parents and Children

The researchers talked about parents, kids, and obesity. They found that if parents were overweight when they were middle-aged, their kids were more likely to be overweight too. Even if just one parent was overweight, their kids still had a higher chance of being overweight later in life.

Furthermore, the study revealed a direct association between the BMI scores of parents and their children. For every four-point increase in the mother’s BMI, their children’s BMI increased by 0.8 points, and for every 3.1-point increase in the father’s BMI, their children’s BMI increased by 0.74 points.

The findings were drawn from the Tromsø study, a population-based study in Norway encompassing two generations of families aged 40 to 59. The analysis included over 2,000 families and accounted for various factors such as age, sex, education, and physical activity level.

Another study from Norway, involving more than 8425 parent-child groups and focusing on adolescence, reaffirmed the strong association between parental and children’s BMI. Overweight or obese parents were more likely to influence their children’s BMI, with the strongest impact observed when both parents were overweight or obese.

While acknowledging the role of genetics and environment in obesity transmission, the researchers emphasized the complexity of the interaction between genes and environment.

Obesity is considered a multifactorial disease, with genetic susceptibility and environmental factors such as diet, physical activity, access to calorie-dense foods, stress, and medication all contributing to its development. Thus, obesity cannot be attributed solely to genetic or environmental factors alone.

How Can Genes Influence Obesity?

Genes play a significant role in how our bodies respond to changes in the environment. Research comparing family members, twins, and adoptees suggest that a considerable part of the variation in weight among adults is due to genetic factors.

Additionally, studies examining genes in obese and non-obese individuals have identified variants that may affect behaviors such as overeating or being sedentary, as well as metabolism, such as difficulty in using dietary fats as energy or a tendency to store body fat. These findings suggest that certain genetic variants may contribute to obesity by increasing hunger and food intake.

While some cases of inherited obesity within families can be traced to specific gene variants (monogenic obesity), most obesity is likely the result of complex interactions between multiple genes and environmental factors, a condition known as multifactorial obesity.

Understanding the obesity epidemic requires considering both genetic and environmental factors. One explanation often discussed is the mismatch between our current environment and genes that evolved during times of unpredictable food sources.

This “thrifty genotype” hypothesis suggests that genes that helped our ancestors survive famines are now challenged in environments where food is abundant year-round. Other hypotheses, such as the role of the gut micro-biome and early-life exposures leading to epigenetic changes, have also been proposed.