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.

Not getting enough shut-eye can cause your body to store more belly fat.

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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.

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).

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.

Refined carbohydrates, including sweets, have been linked to belly fat.

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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.

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.

Did you know that keeping a food diary is one of the most effective ways to manage your weight? Download the MyPlate app to easily track calories, stay focused and achieve your goals!

While men tend to store more fat in their bellies, women generally have less visceral fat than men since they 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.

It's a good idea to incorporate strength training into your exercise routine when you're trying to shed belly fat.

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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.

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.

Read more:
What Causes Belly Fat and How to Get Rid of It - LIVESTRONG.COM