Why Belly Fat is So Hard to Lose

January 22, 2017

by Cathe Friedrich

What separates some women who train from a six-pack is having too much belly fat. You can sculpt firm, strong abdominal muscles through a combination of compound, strength-training exercises, core, and ab exercises, but you won’t see that definition if you have a thick layer of belly fat covering those carefully sculpted muscles.

Unfortunately, when we lose body fat, we can’t control where it comes off. Women often lose body fat from the upper body, particularly the arms, while fat stubbornly clings to the belly. Age is a factor too. Before menopause, you’re more likely to store body fat in your thighs and buttocks, but after your sex hormones drop, fat stubbornly sticks to your mid-section. Why is belly fat so hard to lose?

How You Lose Belly Fat

Anytime you lose body fat, two things happen. First, you mobilize fat or release it from an area. This process is called lipolysis. Once released, fat moves into the bloodstream where cells, such as muscle cells, can grab it and use it as a source of fuel. Secondly, the fat, once taken into a cell, has to be oxidized to produce energy or ATP. So, mobilizing stored fat and sending it into your bloodstream is only the first step. If cells don’t use it as fuel because they already have enough, it can be stored again as body fat.

What causes your body to mobilize fat? Fat cells have receptors that bind hormones that stimulate fat breakdown. These hormones, called catecholamines, have a variety of functions in the human body, one of which is stimulating lipolysis. The receptors for catecholamines on the surface of cells come in two varieties: alpha receptors and beta receptors. Beta receptors work in your favor when you’re trying to shed body fat. They stimulate lipolysis of fat. Alpha receptors aren’t as cooperative. In fact, when catecholamines bind to alpha-receptors, it has the opposite effect – it blocks fat mobilization.

Now, it’s not so hard to see why belly fat resists breakdown. If you have a high ratio of alpha receptors to beta receptors in an area, you’ll have a hard time mobilizing fat. You may also have more alpha receptors in other “problem” areas such as the hips and thighs. This means that even when catecholamines are actively circulating, they don’t readily mobilize fat from areas that have lots of alpha receptors.

In contrast, in areas where the alpha to beta-receptor ratio is often low, like the arms, face, and legs, fat mobilization takes place more easily. If it makes you feel better, men typically have a high ratio of alpha to beta receptors in the belly region. That’s one reason they accumulate more fat around the midline as they age.

The Role that Aging Plays

Women have an easier time losing belly fat before menopause than after the change of life takes place. As you enter menopause, insulin sensitivity declines and insulin rises. This is a factor in how many alpha vs. beta receptors you have in the belly region. As insulin sensitivity declines and you become more insulin resistance, the ratio of alpha to beta increases. This makes it even harder to burn tummy fat!

Plus, other hormonal changes take place that makes loss of belly fat harder. After menopause, you experience a decline in growth hormone while cortisol, the stress hormone stays the same. This shift in hormonal balance favors fat storage around the belly. Plus, struggling to sleep and experiencing stress due to menopause, you might actually get a rise in cortisol and this further impedes belly fat loss.

Genetics

You may, unfortunately, be genetically predisposed to store fat around the belly. Some people have a high ratio of alpha to beta receptors in an area based on genetic influences. That doesn’t mean you can’t lose this stubborn fat but you have to work a little harder.

What Can You Do to Vanquish Stubborn Belly Fat?

Focus at least a portion of your workout time on high-intensity interval training and high-intensity resistance training. Vigorous exercise releases more fat-burning hormones, like catecholamines, as well as growth hormone to help mobilize stubborn body fat. In contrast, moderate-intensity cardio and light weights don’t provide the same stimulus for belly fat loss.

There’s also more post-exercise energy expenditure with high-intensity exercise due to the after-burn effect. One study showed that HIIT training led to greater loss of subcutaneous fat relative to moderate-intensity exercise when both groups burned a similar number of calories. HIIT training was also linked with a reduction in waist circumference.

Contracting your muscles with force also enhances the release of adiponectin, a protein released by fat cells. Adiponectin release boosts fat loss and has anti-inflammatory effects. People who are overweight or obese, particularly those with large amounts of visceral abdominal fat, typically have lower adiponectin levels. This may explain some of the insulin resistance and metabolic issues they experience.

Finally, when you weight train, concentrate more on compound exercises that work multiple muscle groups and large muscles. These exercises burn more calories and create a greater after-burn than isolation exercises that work a single muscle group. In other words, you’ll get more benefit by focusing on squats and deadlifts than biceps curls and triceps kickbacks.

Get over the mindset that moderate-intensity exercise is the key to belly fat loss. In some situations, steady-state exercise, like cycling or running, can be detrimental to belly fat loss. An hour or more of moderate-intensity training can trigger a more sustained rise in cortisol that interferes with belly fat loss.

Diet and Nutrition for Stubborn Belly Fat

If you’re trying to lose stubborn belly fat, there’s no room in your diet for processed foods and foods with added sugar. However, don’t fear dietary fat, as long as you’re consuming healthy ones. Some research suggests that monounsaturated fats, like those in olive oil and avocados, are more favorable for belly fat loss.

The Bottom Line

Yes, belly fat can be a challenge to lose and now you know why. To make it easier:

Do high-intensity training, but give yourself adequate recovery time.
Focus most of your weight training on multi-joint, compound movements.
Eat whole foods, little or no sugar, high fiber, and substitute monounsaturated fats for other fats
Get enough sleep and manage stress.
Be patient. It’s harder to lose belly fat after menopause.

References:

Biology of Sex Differences, 3(1), 13-13. 2012.
MedLine Plus. “Aging changes in hormone production”
Medscape Family Medicine. “Effect of Exercise Training Intensity on Abdominal Visceral Fat and Body Composition”
J Appl Physiol. 2000;89(3):937-46.