FAT, Head to Toe truths

The effects of obesity are revealed in startling detail using a magnetic resonance imaging scanner. It highlights not only the fat lying just under the skin but fat wrapped around organs inside the body. You can see not only the strained joints but crushed lungs and a swollen heart.

When I attended autopsies as a doctor, I saw the stranglehold fat can have around internal organs - and I've stuck to a healthy diet ever since. But the good news is that we can change the picture, however, grim, with the right diet and exercise.

Three-pronged attack

When we over-eat, fat travels around the body causing internal damage in three ways:

● Old-fashioned fat - The fat that forms a layer just under the skin and makes us look and feel heavier. It affects our health by sheer weight, causing joint damage and extra pressure on internal organs.

● Artery-clogging fat - This travels to blood vessels and builds up over time, causing blockages. It can stop blood flow to vital organs such as the heart and brain, leading to strokes and heart attacks.

● Toxic fat - This internal fat, also called visceral fat, creates middle-aged spread and wraps itself around internal organs. It releases toxins that travel around the bloodstream causing chronic inflammation. Long-term, this leads to insulin resistance and a higher risk of diabetes, heart disease and some cancers.

5 ways to target fat

As scary as the effects of fat inside your body are, it's easy to protect yourself. Here's how...

(1) Start walking every day - I believe this is the only way to make your body sensitive to insulin and stop you
over-eating. Start with 10 minutes brisk striding and build up to 30.

(2) Watch your fat intake - Switch to lean cuts of meat, skimmed milk, low-fat spreads and cook with good fats such as olive oil.

(3) Reduce your waist - It should measure no more than 32in if you're a woman and 37in if you're a man. Just shaving off a couple of inches reduces the amount of toxic fat in your body.

(4) Control portions - The average portion size has gone up 25% in the past 20 years. As a rule of thumb, fill half your plate with veg, a quarter with lean protein like chicken, and a quarter with starchy carbs such as pasta or rice.

KIDNEYS A heavy layer of fat around the kidneys forces them to work much harder. Being overweight raises kidney failure risk.

HIPS, KNEES and ANKLES The extra weight places additional pressure on joints, wearing away cartilage, increasing risk of pain and arthritis.

EYES Fatty deposits which build up in the eye's blood vessels can raise the risk of diseases that cause blindness -
age-related macular degeneration, cataracts, glaucoma and diabetic retinopathy.

PELVIC FLOOR Being overweight puts pressure on pelvic floor muscles, which can cause piles and incontinence.

OVARIES AND UTERUS Body fat produces oestrogen, which can affect fertility. Obese women are nearly 70% more likely to have a miscarriage, says a US study.

BRAIN Blood flow is reduced when fatty deposits build up and narrow the arteries that supply the brain, increasing your risk of stroke. This type of blockage is also linked to Alzheimer's and other forms of dementia.

MIND Research indicates that visceral fat can lower your mood by increasing production of stress hormone cortisol, and reducing levels of feel-good endorphins.

UPPER ARMS An excess layer of fat here puts an increased load on the shoulder joint, resulting in pain and later difficulty raising your arm.

FOR MEN An extra layer of fat around the stomach and thighs can cause testicles to overheat, resulting in poor sperm quality. Obese men are 40% more likely to have low sperm counts.

FEET Being overweight puts pressure on the ligament that runs from your heel to the ball of your foot, causing pain and inflammation.

KIDNEYS A layer of heavy fat around the kidneys forces them to work much harder. Swedish researchers found that being overweight tripled the risk of kidney failure. Obese people, especially women, are also more likely to develop cancer of the kidney.ABDOMEN Toxic fat around internal organs causes a bulge in the tummy area. Chemicals and hormones produced can trigger metabolism changes, hormone imbalances and greater risk of heart disease, diabetes and breast or colon cancer.

HEART Fat that forms around the heart produces inflammatory proteins which are linked to hardening of the arteries. A build-up of fatty deposits in arteries supplying the heart cause angina and increased risk of heart attack.

HEAD AND NECK Research shows a link between excess weight and headaches. One theory is that the extra weight puts pressure on nerves in the neck, causing pain.

THROAT Carrying excess weight in the neck area can compress the airway, causing snoring and sleep apnoea. People with sleep apnoea have a higher risk of heart attack.

LUNGS Excess body weight crushes the chest, reducing lung function, while fat in the abdomen can also push against the diaphragm when the person lies flat, causing shortness of breath.

EARS Blocked blood vessels mean decreased blood flow resulting in a lack of oxygen and failure to remove toxic waste. This may cause hearing damage.