Beer belly, spare tire, gut — whatever you want to call it, belly fat is caused by many different things, from lack of exercise to poor diet to genetics.
Having a bigger waistline can be a major hazard to your health, but with the right lifestyle changes, you can shed that unwanted belly fat. But first, you need to know exactly how it got there.
Belly Fat 101
There are two types of fat stored in or around your abdomen — subcutaneous (the soft kind that you can pinch) and visceral (hard fat that's deep down around your organs). Approximately 90 percent of body fat in most people is soft fat that's located under the skin, according to Harvard Health Publishing, and although many people find it unattractive, that type of fat actually acts as insulation and a source of energy, producing various beneficial molecules to help you maintain your weight.
The other type is visceral fat — intrabdominal hard fat that can make your belly protrude (think: beer belly). It's the more dangerous of the two, per Harvard Health Publishing, since it produces a large number of molecules with possible detrimental health effects such as insulin resistance, high blood pressure and high cholesterol as well as heart disease, type 2 diabetes and certain cancers — even for those with a normal body mass index (BMI).
Belly Fat Culprits
1. Inactivity and poor diet are the main causes of obesity and fat gain in general. If you're consuming more calories than you burn every day — especially via foods that have little nutritional value — then you're going to pack on the pounds and gain inches everywhere, including your waistline. A major study published August 2014 in the American Journal of Medicine saw substantial increases in weight and waist circumference in both men and women as physical activity decreased over a 22-year span.
2. Age, sex and genetics also play a role in belly fat gain. As you age, muscle mass naturally decreases, especially if you're more sedentary. And a decrease in muscle means you're not burning as many calories, which makes it harder to maintain a healthy weight and keep the fat off, per the Mayo Clinic.
Older women may notice an increase in belly fat as they age even if they're at a healthy weight, due to menopause and a decrease in estrogen production, which influences where fat is distributed, according to the University of Rochester Medical Center.
A review published November 2019 in Arteriosclerosis, Thrombosis, and Vascular Biology not only states that sex hormones affect fat distribution in men and women, but also says that there are many loci (the physical location of a gene, like a genetic street address) with "sexual dimorphic associations" with belly fat. In other words, fat gain and distribution may not only be hereditary, but certain genes linked with belly fat are sex-specific, and most have a stronger effect in women.
3. Sleep deprivation is also found to increase belly fat accumulation, according to the National Sleep Foundation. Research has found that people who sleep less than five hours at night gain more belly fat over the years compared to those who sleep more than six hours. An August 2014 review in the Annals of Medicine goes into it further, linking sleep deficits to increased food intake, decreased energy expenditure and changes in appetite-regulating hormones levels. It also points the finger at multimedia usage (read: screentime) for keeping you up at night.
4. Being stressed out is another culprit. Studies have shown the close association between increased levels of the hormone cortisol and deep abdominal fat deposits, according to The American Institute of Stress.
Foods that Cause a Bigger Belly
There's a reason why whole grains win over white: Refined carbohydrates — such as white bread, pasta, rice, chips, sweets and sugary drinks — have been linked to weight gain, diabetes and heart disease, per the Harvard T.H. Chan School of Public Health. Refined carbs are grain-based foods that have the bran and germ extracted during processing, which means they offer calories without fiber or any other nutritional value.
Read more: 16 Diet-Friendly Healthful Carbs
These foods cause sharp spikes in blood sugar and can boost blood triglyceride levels, according to Harvard Health Publishing, and high triglyceride levels can lead to more fat stored around the waist. A study published November 2014 in Mediators of Inflammation showed that a high intake of refined carbs is a risk factor for inflammation, insulin resistance and belly fat.
Why Do Women and Men Gain Fat Differently?
While men tend to store more fat in their bellies (thanks to testosterone), women generally have less visceral fat than men; estrogen causes them to gain much of their fat subcutaneously in the thighs and buttocks to aid in pregnancy and breastfeeding. As menopause approaches, though, estrogen levels decrease, testosterone increases and there is a redistribution of fat to the belly.
Of course, there are those women with androgen excess early on — like those with polycystic ovary system (PCOS). Researchers concluded in a September 2019 study in Frontiers of Hormone Research that androgen excess can adversely affect insulin sensitivity and promote visceral fat.
What's also interesting is that although women have less visceral fat as younger adults, severe obesity is more prevalent in women than men, according to a 2017 review published in Human Reproduction Update. Again, thanks to estrogen (which increases and decreases during different phases of the menstrual cycle), women may be more prone to overeating, causing weight and fat gain.
How to Shed Belly Fat
1. Move that body! Visceral fat is easier to lose as it responds to the same diet and exercise that helps with weight loss. Moderate-intensity activity like cardio for 30 to 60 minutes a day will help combat excess fat and pounds. But strength and resistance training are also recommended because muscle mass helps to burn more calories and fat. A study published February 2015 in Obesity concluded that, out of various physical activities, strength training had the biggest influence on waist circumference change in men.
Read more: Can I Lose Belly Fat by Lifting Weights?
2. Fix your diet. Look closely at what and how much you're eating on the regular. Cut down on refined carbs, sugar and saturated and trans fat, and add in more lean protein, fruits, veggies, whole grains and healthy fats like olive oil, avocado and nuts.
Also keep in mind that while eating wholesome food is a major factor, cutting calories is key. One pound of stored fat contains approximately 3,500 calories. So, creating a daily 500-calorie deficit helps you lose about 1 pound of fat weekly.
"It's not just about consuming these healthier carbohydrates to lose and keep off belly fat, but to feel good about consuming them to make it into a healthy behavioral pattern that can lead to a lifestyle of less belly fat," Jim White, RDN, ACSM, owner of Jim White Fitness and Nutrition Studios, tells LIVESTRONG.com.
3. Take time to relax — and prioritize sleep. Since sleep deprivation may be causing weight and fat gain, address any poor sleep habits that are preventing you from getting the recommended seven to nine hours each night. If you're stressed, exercise and yoga are great releases, as well as meditation, therapy or whatever you feel is self-care.
4. Get help. Hey, no one said making these lifestyle changes would be easy. If you need some guidance or support, make an appointment with a professional, such as a doctor who specializes in weight loss, registered dietitian or a personal trainer.
- Harvard Health Publishing: "Taking Aim at Belly Fat"
- Mayo Clinic: "Belly Fat in Women: Taking — and Keeping — It Off"
- American Journal of Medicine: "Obesity, Abdominal Obesity, Physical Activity and Caloric Intake in US Adults: 1988-2010"
- National Human Genome Research Institute: "Locus"
- National Sleep Foundation: "Sleep Linked to Gains In Abdominal Fat"
- Annals of Medicine: "Sleep Debt and Obesity"
- The American Institute of Stress: "Stress, Cortisol and Abdominal Fat"
- Harvard Health Publishing: "Healthy Eating for Blood Sugar Control"
- SF Gate: List of Refined Carbs
- Mediators of Inflammation: "Excessive Refined Carbohydrates and Scarce Micronutrients Intakes Increase Inflammatory Mediators and Insulin Resistance in Prepubertal and Pubertal Obese Children Independently of Obesity"
- Arteriosclerosis, Thrombosis, and Vascular Biology: "Sex Differences in Genomic of Adipose Distribution and Related Cardiometabolic Disorders"
- Frontiers of Hormone Research: "The Role of Androgen Excess on Insulin Sensitivity in Women"
- Human Reproduction Update: "Ovarian Hormones and Obesity"
- Mayo Clinic: "Belly Fat in Men: Why Weight Loss Matters"
- Obesity: "Weight Training, Aerobic Physical Activities, and Long-Term Waist Circumference Change in Men"
- Mayo Clinic: Counting Calories: Get Back to Weight-Loss Basics
- Harvard Health Publishing: Abdominal Fat and What to Do About It
- University of Rochester Medical Center: "What Does Estrogen Have To Do With Belly Fat?"
- Harvard T.H. Chan School of Public Health: "Beyond Willpower: Diet Quality and Quantity Matter"