For most people, gaining weight is something to avoid. And yet, obesity continues to be called a public health crisis by the Centers for Disease Control and Prevention with almost 40% of the American adult population considered to be obese. (1) The fact is, the cause of weight gain could be something other than diet and exercise, something unexpected that may not even be on a person’s radar. To achieve sustainable weight loss, you should look at these three factors that can influence weight gain.

1. Stress can cause weight gain

Stress activates the hypothalamic-pituitary-adrenal (HPA) axis which initiates the release of powerful hormones and neurotransmitters to prepare the body to fight. But when the HPA axis activation becomes chronic, it can contribute to weight gain. (2) One key stress hormone, cortisol, is particularly troublesome because when it is chronically elevated, it causes fat to be stored around the waistline; and the higher the cortisol level, the more fat that is stored. (3)

Also known as abdominal obesity, when someone has a higher than average waist circumference, they are at increased risk of many illnesses including heart disease and diabetes. A 2019 study showed that even non-obese individuals who had a larger waist circumference were still at higher risk of these illnesses. (4) This is why keeping track of waist circumference and losing abdominal weight, in particular, is so important, especially during times of stress.

Stress can lead to increased cortisol and fat storage, poor eating habits, and lack of sleep.

Also when someone is under stress there is a tendency to eat more, choose unhealthy foods, and sleep less, all of which cause weight gain. (5) A vicious cycle can ensue beginning with the stress that causes increased cortisol and fat storage, poor eating habits, and lack of sleep. Under this scenario, it can be very difficult to lose weight. Focusing on natural sleep aids will help break the cycle. Also, there are dietary supplements that can help the body better cope with stress.

2. Hormonal imbalance can cause weight gain

Cortisol isn’t the only hormone that can cause weight gain. An imbalance of hormones, in general, can lead to obesity. Sex hormones like estrogen, progesterone, and testosterone all play a role in weight loss and weight gain. This can be especially frustrating for perimenopausal and menopausal women because hormonal imbalance is a hallmark of these life stages.

Estrogens help regulate metabolism and energy so when there is a rapid decline in estrogen levels, as there is with menopause, there is a corresponding reduction in metabolism and energy balance that can lead to weight gain. (6) Therefore, menopausal women who are trying to lose weight will likely benefit from strategies to boost metabolism including diet, exercise, and certain dietary supplements.

3. Diseases can cause weight gain

Weight gain can be a sign of an underlying illness so it’s important to rule out any potential medical causes. Here are some common diseases that can cause weight gain.


Can depression cause weight gain? Yes. Research clearly shows that people who have symptoms of depression are also at an increased risk of gaining weight. (7)


The medication used to treat type 2 diabetes is insulin. Patients are sometimes concerned that taking insulin will cause weight gain. Insulin can indeed cause weight gain in the first year of use; however, this should not be a deterrent for those patients who need insulin. (8)


An underactive thyroid is definitely linked to weight gain. There is a correlation between high leptin levels and hypothyroidism, which can lead to poor appetite control and increased fat storage for people who have an underactive thyroid. (9)

Exercising regularly helps with treating the weight gain associated with polycystic ovary syndrome (PCOS).

Ovarian cysts

The development of ovarian cysts is a hormonal issue that can lead to polycystic ovary syndrome (PCOS). Weight gain is a common occurrence with women who have PCOS. (10) Losing weight is a key strategy in treating this condition.

Sleep apnea

Sleep apnea is a common sleep disorder that often goes undiagnosed. With this condition, breathing repeatedly stops and starts during sleep. Sleep apnea can be a serious health condition and obesity is one of the main contributors. (11)

The bottom line

Yes, we all know that diet and exercise can influence weight loss and weight gain. But in some cases, that’s not the whole story. Sometimes, weight gain can come from stress, hormonal imbalance, or even an undiagnosed or diagnosed illness. To achieve lasting weight loss and maintain normal body weight, you should look at all aspects of weight gain.

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  1. Centers for Disease Control and Prevention. Adult obesity facts. Accessed online January 2020.
  2. Scott KA, Melhorn SJ, Sakai RR. Effects of Chronic Social Stress on Obesity. Current Obesity Reports. 2012;1(1):16–25.
  3. Jackson, SE, Kirschbaum C, Steptoe A. Hair cortisol and adiposity in a population-based sample of 2,527 men and women aged 54 to 87 years. Obesity. 2017;25(3).
  4. Lukacs A, Horvath E, Mate Z, et al. Abdominal obesity increases metabolic risk factors in non-obese adults: a Hungarian cross-sectional study. BMC Public Health. 2019;19:1533.
  5. Lucassen EA, Cizza G. The Hypothalamic-Pituitary-Adrenal Axis, Obesity, and Chronic Stress Exposure: Sleep and the HPA Axis in Obesity. Current Obesity Reports. 2012;1(4):208–215.
  6. Kozakowski J, Gietka-Czernel M, Leszczyńska D, Majos A. Obesity in menopause – our negligence or an unfortunate inevitability? Menopause Review. 2017;16(2):61–65.
  7. Sutin AR, Zonderman AB. Depressive symptoms are associated with weight gain among women. Psychological Medicine. 2012;42(11):2351–2360.
  8. Naeem N, Basit A, Shiraz A, et al. Insulin-associated weight gain in type 2 diabetes and its relation with caloric intake. Cureus. 2019;11(7).
  9. Sanyal D, Raychaudhuri M. Hypothyroidism and obesity: An intriguing link. Indian Journal of Endocrinology and Metabolism. 2016;20(4):554–557.
  10. Sam S. Obesity and Polycystic Ovary Syndrome. Obesity Management. 2007;3(2):69–73.
  11. Jehan S, Zizi F, Pandi-Perumal SR, et al. Obstructive Sleep Apnea and Obesity: Implications for Public Health. Sleep Medicine and Disorders. 2017;1(4).