Can Men Really Grow ‘Dad Bods’ Because of Hormones?

The term “dad bod” has grown from a pop culture joke into a widely recognized description of men who gain a bit of weight, lose muscle tone, and develop a softer physique after becoming fathers. But is this change only about eating habits, busy schedules, and less exercise—or is there a deeper biological factor at play? Recent scientific studies suggest that male hormones, particularly testosterone, may play a surprising role in shaping this transformation. In this article, we’ll dive deep into the science of male hormonal changes, lifestyle factors, and cultural perceptions behind the dad bod phenomenon. At betterhealthfacts.com, we believe in separating myths from facts to give readers medically valid insights.

What Exactly Is a “Dad Bod”?

A “dad bod” refers to a body type commonly described as slightly overweight, with less muscle mass and some fat accumulation around the abdomen. Unlike obesity, it doesn’t usually indicate extreme weight gain but rather a softer, less athletic look. While many people joke about it, the phenomenon has raised serious questions: is it a biological inevitability of fatherhood, or just lifestyle-related weight gain?

Testosterone and Fatherhood: A Biological Connection

One of the most studied hormonal shifts in men after fatherhood is a decrease in testosterone. Testosterone is the primary male sex hormone that regulates muscle growth, fat distribution, energy levels, and libido. Several studies have confirmed that men often experience a drop in testosterone levels after becoming fathers.

According to research published in the Proceedings of the National Academy of Sciences, new fathers experience a measurable decrease in testosterone levels, which may help them adapt to parenthood by becoming more nurturing and less aggressive.

This decline in testosterone can influence body composition. Lower testosterone is linked with reduced lean muscle mass, increased fat storage (especially in the abdominal area), and slower metabolism. This hormonal shift makes it biologically easier for men to develop the typical dad bod appearance.

Why Would Evolution Favor Lower Testosterone in Fathers?

From an evolutionary perspective, the drop in testosterone makes sense. Higher testosterone is associated with risk-taking, aggression, and mating behavior, while lower testosterone encourages nurturing, caregiving, and cooperative parenting. By lowering testosterone, men may become more invested in their offspring and less focused on competing for new mates. However, the same hormonal shift may have an unintended side effect: making it harder to maintain a lean, muscular physique.

How Much Does Testosterone Really Drop?

On average, studies suggest that men can experience a testosterone drop of 20–30% after becoming fathers. The extent of this decrease depends on factors like the man’s age, the intensity of parenting responsibilities, and overall health. While not every father experiences a dramatic drop, the trend is consistent enough across cultures to suggest that biology plays a role in the dad bod.

Other Hormonal Changes Beyond Testosterone

While testosterone gets most of the attention, other hormones shift in men after they become fathers. Prolactin, oxytocin, and cortisol levels may also change. These hormones help men bond with their infants and manage the stress of parenting, but they can also influence metabolism and appetite.

Dr. James Rilling, an anthropologist who studies fatherhood, notes that “men show hormonal changes when they become dads, including rises in prolactin and oxytocin, which help them respond to their babies’ needs.”

Prolactin, usually associated with mothers and breastfeeding, has been found at elevated levels in fathers as well, and may contribute to weight gain by influencing appetite and fat storage. Oxytocin, the so-called “love hormone,” encourages bonding but may also subtly affect eating behavior and stress regulation. Cortisol, the stress hormone, often rises with sleep deprivation and childcare challenges, and prolonged high cortisol is known to promote belly fat accumulation.

Lifestyle Shifts That Encourage the Dad Bod

Hormonal changes alone don’t explain the dad bod. Lifestyle plays a huge role. Fatherhood often brings dramatic changes to a man’s daily routine, which can indirectly contribute to body changes:

• Sleep Deprivation: Caring for an infant often means interrupted sleep. Sleep loss lowers testosterone, raises cortisol, and increases cravings for high-calorie foods.
• Reduced Physical Activity: New fathers may have less time for the gym or sports due to parenting responsibilities, leading to muscle loss and fat gain.
• Dietary Changes: Quick meals, snacking, and finishing children’s leftovers can increase calorie intake.
• Stress Eating: Parenting stress may lead to comfort eating, which further contributes to weight gain.

The Combined Effect: Hormones + Lifestyle

It’s not just biology or lifestyle—it’s both. Lower testosterone makes it harder to maintain muscle mass, while stress, poor sleep, and lack of exercise create the perfect environment for fat storage. This combination explains why so many men notice changes in their body after fatherhood.

Is the Dad Bod Inevitable?

No, it’s not inevitable. While hormonal shifts do play a role, they are not destiny. Men can take steps to manage these changes:

• Maintaining a consistent exercise routine, even if shorter and less intense than before.
• Focusing on strength training to counteract muscle loss from reduced testosterone.
• Eating a balanced diet rich in protein, healthy fats, and fiber to prevent fat gain.
• Prioritizing sleep and stress management to stabilize hormones.
• Monitoring health for signs of hormonal imbalance in men, especially after age 30.

When to Worry: Beyond the Dad Bod

While a mild dad bod is not necessarily unhealthy, excessive weight gain and low testosterone can increase risks for chronic health problems. Abdominal obesity is strongly linked with cardiovascular disease, insulin resistance, and type 2 diabetes. In fact, declining testosterone in men is associated with a higher risk of metabolic syndrome, which combines obesity, high blood pressure, and abnormal cholesterol.

Doctors warn that while some weight gain after fatherhood is normal, persistent fatigue, low libido, and significant muscle loss may be signs of an underlying hormonal issue that requires medical attention.

In some cases, low testosterone may also be linked to increased risk of heart disease. That’s why it’s important for men to track their health and discuss changes with a healthcare provider.

The Role of Age in the Dad Bod

It’s worth noting that testosterone naturally declines with age, beginning in a man’s late 20s or early 30s. Fatherhood often coincides with this period, amplifying the effects. For example, a man in his 30s who becomes a father may face both age-related decline and fatherhood-related decline in testosterone at the same time, making him more vulnerable to weight gain and body composition changes.

Modern Pressures and Hidden Health Risks

In today’s fast-paced world, men face additional challenges beyond parenting. Sedentary desk jobs, processed foods, and chronic stress already put men at risk of obesity and metabolic disorders. When combined with fatherhood-related hormonal changes, the risk compounds. This may help explain why heart attacks are increasing in men under 40, with stress, weight gain, and lifestyle factors playing critical roles.

The Cultural Side of the Dad Bod

The dad bod isn’t just a medical term—it’s also a cultural phenomenon. Some see it as attractive, symbolizing stability, maturity, and confidence. Others see it as a sign of neglect. Social acceptance of the dad bod can make men less motivated to maintain fitness, while constant jokes about it can increase body image stress. Understanding that real biological and lifestyle factors are involved can help shift the conversation from ridicule to empathy and health awareness.

Can Hormonal Changes Affect Fertility Too?

Yes, hormonal shifts that lead to a dad bod can also influence fertility. Lower testosterone can reduce sperm quality and libido. This is one reason why more men are now becoming aware of reproductive health issues. Interestingly, an increasing number of men are taking proactive steps to secure their fertility, such as choosing to freeze their sperm before age or lifestyle factors take a toll.

Practical Tips for Men to Counter the Dad Bod

While it’s natural for fatherhood to change your routine, there are practical steps to maintain health:

• Short Workouts: Even 20–30 minutes of exercise 4–5 days a week can help preserve muscle.
• Family Activities: Turn childcare into exercise by walking with a stroller, playing active games, or carrying your baby.
• Meal Prep: Preparing healthy meals in advance prevents reliance on processed foods and snacking.
• Mindful Eating: Avoid finishing your children’s leftovers to reduce extra calorie intake.
• Medical Checkups: Regular blood tests to track testosterone, cholesterol, and blood sugar can help prevent long-term issues.

Final Thoughts

The dad bod is more than just a cultural stereotype—it reflects real biological and lifestyle changes men face after fatherhood. While hormones, especially testosterone, do play a role, lifestyle factors like sleep, stress, diet, and exercise amplify the effect. The good news is that men are not powerless. With awareness and small but consistent lifestyle changes, it is possible to counteract the hormonal and environmental shifts that lead to a dad bod. At the same time, acknowledging that biology plays a part can help reduce the stigma and humor around this body type, replacing it with compassion and informed choices. At betterhealthfacts.com, we encourage men to see the dad bod not as a joke, but as an opportunity to take control of their health for themselves and their families.