If you thought fat was just fat, you’re dead wrong. Fat is actually a very important organ just like your thyroid gland or kidney. Fat produces hormones and, in excess, will kill you.

If you thought all fat was the same you’re mistaken. There are two very important different fats that you must know about.

If you thought there was nothing you could about the fat, you’re wrong again. You can make a big difference and I’m going to show you how.

First, you need to learn the difference between visceral fat (VAT) and subcutaneous fat (SAT). VAT is the fat in your belly. Not the paunch hanging over your belt, that’s the beer and chocolate storage, VAT is the fat IN the abdomen surrounding all your organs, the kidney, the liver, the spleen, the pancreas and your intestines.

Overall, visceral fat is just a small amount of our total body fat. In a slightly overweight middle-aged man like me (OK I’m not slightly overweight) it represents about 15% - 20% of total fat. In a pre-menopausal woman it may be about 10% to 15% of total fat. So what’s the big deal? It’s just some more fat, right? You know the answer is a big NO or I wouldn’t have posed it.

We all know that being overweight leads to all sorts of health problems blah, blah, blah. Well the effects of obesity result from two factors: the increased mass of fat tissue and the increased secretion of harmful chemicals from the enlarged fat cells. Guess which fat most of these harmful chemicals come from – you’re right again, the VAT! And this is probably the most defining aspect of your decision to lose weight, are you losing for health, beauty or both. If the answer is health then focus on losing VAT. If it is beauty or both then you need to lose total fat, i.e. SAT and VAT.

We have known for decades that the “Apple” body was much more dangerous than the “Pear” body, but now we now why. Since the advent of CT Scans and MRI’s we have been able to see and measure VAT. People with the “Apple” body have much more VAT than the “Pears”. We even know that some skinny people have a great deal of VAT that you can’t see with the naked eye, placing them at high risk of various health problems. We all carry weight different and there are ethnic, gender and age differences.

Blue = SAT Red = VAT

Unfortunately, getting a CT or MRI to determine our fat content is not cost effective. But, there are some clinical indicators of VAT. In men, the best and most reliable is our waistline. For women it is just simply your total weight. One study, in 1995, attempted to generate an equation to predict VAT in men and women. The best they could do was predict about 60% of the actual VAT. Another study in children published in January 2006 also found that the waist circumference was the single best predictor of VAT and was about 60% accurate. However, both studies were more successful in predicting SAT. Using the BMI they could predict about 88% of SAT.

Just in case you forgot, here are some of the health related problems from fat:

Health issues related to increased fat mass

• psychological problems (depression, being stigmatized, poor self-esteem),
• sleep apnea (probably from the increased fat at the neck)
• Disease of bones, joints, muscles, connective tissue, and skin. The extra weight quickly tears up the knees and ankles. But cartilage and bone in other areas are affected also. Skin changes include stretch marks (striae); fat lobules; pigmentation in the folds of neck, knuckles, and extensor surfaces (Acanthosis nigricans)

Health issues related to chemicals secreted by enlarged fat cells include:

• diabetes mellitus, insulin resistance, and the metabolic syndrome,
• nonalcoholic fatty liver disease and nonalcoholic steatohepatitis,
• gallbladder disease,
• hypertension or high blood pressure. One estimate suggests that control of overweight would eliminate 48% of hypertension in whites and 28% in blacks. For each decline of 1 mm Hg in diastolic (the lower number) blood pressure, the risk of a heart attack decreases by 2-3%.
• Heart disease. The Nurses’ Health Study indicated that the risk of heart disease in women increased by over 3 times if the BMI is over 29 compared to a BMI under 21. Between 27 and 29 the risk is 1.8.
• Cancer. Men have increased risk of colon, rectum and prostate. Women have more cancers of the reproductive organs and gallbladder.
• Hormone changes. Irregular menses and frequent cycles without production of an egg, and reduced fertility.

What are the net effects of obesity?

The Framingham Study estimated that nonsmoking women with a BMI over 25 at age 40 lost 3.3 years and men 3.1 years. A BMI over 30 increased that to 7.1 and 5.8 years respectively. The Third Health and Nutrition Examination Survey found the optimal BMI for longevity in whites was 23-25, and in blacks was 23-30. This study suggested there was important ethnic differences in the health manifestations of obesity.

My final ramblings

The absolute in medicine is that there are no absolutes. All the bad chemicals are not just from VAT. There are no methods of just eliminating VAT or SAT. But, here are some general guidelines.

Exercise – numerous studies have shown that exercise is extremely effective, and probably the best way, of reducing VAT. We think it is because of the sympathetic stimulation of exercise that VAT is so effectively eliminated. Studies also show that if you just exercise and don’t diet VAT is reduced as effectively as diet and exercise combined. And yes, you can exercise a lot, not see any changes on the bathroom scale, and still lose a great deal of VAT and a smaller waistline. Studies show that with exercise muscle mass remains constant and body fat % is reduced even when total body weight is unchanged. Diet without exercise will lose muscle mass.

Diet – if you lose weight with diet you lose both SAT and VAT. But some studies suggest that improved insulin resistance requires exercise and still other studies suggest you do not lose VAT without exercise.

My thoughts. If you lose significant weight, over 10%, with just diet you probably will lose both SAT and VAT. If you just exercise without diet you will lose VAT, some SAT but your total weight probably won’t change much. So guess what? You need to diet and exercise. You need to change your lifestyle!

Life's plan