As time passes, our body experiences significant physiological changes that can directly impact weight. One of the most notable is the gradual loss of muscle mass, a process that begins around middle age. About 1% of muscle mass is lost each year, which affects strength and metabolism, that is, the speed with which calories are burned. This is because smaller, less active muscles consume fewer calories.
By maintaining the usual diet without adjusting it to this new metabolic reality, it is likely that more calories will be consumed than the body needs. Extra unused calories are stored as fat. This process can be gradual and almost imperceptible, leading to long-term weight gain that many people fail to directly associate with aging, as revealed by Harvard University.
Not tackling stress
As time goes by and responsibilities increase, managing stress can become more complicated. A consistently high level of cortisol, known as the stress hormone, may play an indirect role in weight gain. This hormone helps the body replenish its energy reserves, which can increase appetite (as the body interprets that it needs more energy) and promote the accumulation of unused energy in the form of fat.
“Chronic stress often leads to compulsive behaviors, such as eating comfort foods, which are often loaded with sugars, unhealthy fats, extra calories and salt. These foods provide momentary satisfaction, but contribute significantly to positive energy balance and fat storage,” highlights Concepción Martínez, a dietician-nutritionist specialized in obesity and sports nutrition.
Sleeping problems
Sleep disorders have a direct effect on weight. Not getting enough sleep, such as sleeping six hours or less per night, can upset the body’s hormonal balance, affecting the hormones that regulate appetite. Insufficient sleep has been found to be associated with higher levels of hormones that stimulate appetite and lower levels of hormones that cause feelings of satiety.
Additionally, lack of sleep is also linked to elevated levels of cortisol, which, as mentioned above, can contribute to packing on the pounds. This cycle of poor sleep and hormonal dysregulation can lead to gradual and sustained weight gain, creating a vicious cycle that is difficult to break.
Hormonal changes
In both men and women, sex hormone levels change throughout life and can have a direct impact on body weight. In women, low estrogen levels are not only associated with sleep problems, but also with increased body fat. In men, the decrease in testosterone levels is related to a reduction in muscle mass.
These hormonal changes can alter body composition, favoring the increase in fat and a decrease in muscle mass, which has a direct impact on basal metabolism and, therefore, weight.
Can hide pathologies
Weight gain can be a symptom of different health conditions, some of them serious. For example, in the case of heart failure, this increase may be due to fluid retention, which manifests itself as swelling in the feet, ankles, legs or abdomen.
Other health problems that can cause weight gain include diabetes, certain kidney diseases, sleep apnea, and thyroid disorders. These conditions can alter metabolism or cause changes in fluid retention, which will add pounds to the scale.
This type of weight gain is often accompanied by other symptoms, such as fatigue or shortness of breath, which can help identify the underlying cause. “If an inexplicable weight change occurs, whether it is above or below our usual weight, we should always consult a specialist,” warns Martínez.
Medicines
Some medications can have weight gain as a side effect. An example is prednisone, which can cause fluid retention and therefore an increase in body weight.
Other medications can affect brain chemicals that regulate appetite, leading to increased appetite. This includes certain antidepressants, antihistamines, antipsychotics, and beta blockers.
Having more appetite than usual can lead to excessive food consumption and, consequently, weight gain. This effect is particularly challenging because patients who need these medications to treat their health conditions must balance the benefits of the treatment with its potential side effects.
Other causes
There are emerging and research theories about the causes of weight gain. One of them is the impact of eating food late at night. A 2022 Harvard study suggests that dining late can increase appetite during the day, slowing metabolism and increasing body fat.
The gut microbiome, that is, the set of microbes that live in our intestine, could play an important role in appetite, metabolism, blood sugar levels and fat storage.
Professionals warn that, in the face of recent or significant weight gain, it is essential to consult a doctor. This may look for new underlying conditions or evaluate whether current medications could be influencing weight. Additionally, it may be beneficial to consult a dietitian to determine the appropriate caloric intake for the individual’s current needs.
It should be noted that the most effective strategy to control weight is to adopt a healthy lifestyle. This includes a diet rich in fruits, vegetables, legumes, and limited amounts of whole grains and starchy vegetables, along with sufficient amounts of lean protein to help build muscle. Avoiding eating late at night, sleeping seven to nine hours a night, exercising daily, and strength training at least twice a week are essential habits.
