The most frustrating aspect of dieting is the fact that, despite all efforts, weight some-times won't come off-particularly that spare tyre around the middle. Those with this problem consider themselves victims of a bad genetic throw of the dice, lumbering them with a sluggish metabolism.
However, new research has found that the most likely cause has to do with insulin secretion, which means that it's mostly to do with factors within your control.
The new evidence from Boston is that people who have high levels of circulating insulin have far more difficulty losing weight than those with normal insulin levels (JAMA, 2007; 297: 2092-102). Such people also have impaired or desensitized insulin receptors, so the body's only remedy is to crank up the production of insulin.
When insulin is released, it inhibits the ability of the hormone lipase to burn fat as fuel. The body then turns to burning muscle and carbs-which stimulates your appetite.
Insulin regulates glucose sugar in blood cells and helps it to enter other body cells to be used as fuel or stored for future use. Made by the pancreas, insulin is released into the blood when blood glucose levels rise after eating.
The body becomes insulin-resistant largely when it is so bombarded with insulin that it turns down receptor activity in an attempt to protect itself from the toxic effects of high insulin levels. As the body stops recognizing insulin, it produces more and more simply to regulate the amount of glucose in the blood. This condition heralds diabetes, when the pancreas can no longer produce adequate insulin to control blood glucose levels. Even more worrying, insulin resistance can also lead to all the major degenerative diseases, including heart disease, high blood pressure, stroke and even cancer.
Insulin resistance may also be brought about by:
- a diet high in processed foods, which usually involves large amounts of sugar or glycaemic index (GI) foods.
- stress. Being constantly on fight-or-flight alert increases insulin production so that the glucose in body cells can be used for energy to respond to the stressor. It also causes the body to crave high GI foods for instant energy. As Marilyn Glenville has written in her book Fat Around the Middle (Kyle Cathie, 2006), eating fatty or sugary foods during bouts of stress is usually deposited around the middle "because it is close to the liver, where it can most quickly be converted back into energy if needed".
- lack of exercise. Evidence from Harvard (Annu Rev Med, 1998; 49: 235-61) shows that just a single bout of exercise increases the rate of glucose uptake into the skeletal muscles that have been put to work. Furthermore, any exercise training can help to correct insulin resistance by causing an increase in glucose transporters. Although some studies do not show that exercise helps diabetics improve overall glucose control, there is copious evidence that exercise can help to prevent non-insulin-dependent (type 2) diabetes.
- lack of chromium. After conducting a study of thousandsof patients over many years, nutritional pioneer Dr Stephen Davies discovered that, as patients age, they invariably develop low levels of chromium. Adequate amounts of this nutrient are necessary for insulin receptors to work and, indeed, at least 15 controlled trials show that taking high levels of chromium (10 times the average) can reduce insulin resistance and normalize blood sugar levels (Diabetes Technol Ther, 2006; 8: 677-87).
What to do
Eat organic wholefoods
-Determine your metabolic type and eat the right amount of carbohydrates for your type (see www. healthexcel.com for a simple test to see whether you should eat more carbohydrates or protein)
-Eat little and often, and don't be afraid to 'graze' on healthy snacks like nuts and seeds. Don't diet by cutting down your frequency of eating. As Marilyn Glenville points out, when you restrict food or skip a meal, your body assumes you're suffering a famine and stores fat
-Cut out all 'junk' processed foods and sugars
-Take essential fatty acids (particularly the omega-3s) which help against insulin resistance
-Take certain supplements. Besides a good multi-vitamin/mineral with adequate B, C, zinc, magnesium and manganese, Glenville suggests you also take:
-chromium (200 mcg), to stabilize blood sugar levels in the non-diabetic (J Trace Elem Exp Med, 1999; 12: 71-83). But be careful not to exceed 600 mcg/day, even if diabetic; one patient taking 1000 mcg/day suffered liver and kidney damage (Ann Pharmacother, 1998; 32: 428-31)
- Siberian ginseng (100 mg)
- coenzyme Q10 (25 mg)
- alpha-lipoic acid (100 mg)
- green-tea extract (50 mg)
- amino acids: N-acetyl cysteine, l-carnitine, l-tyrosine, l-arginine, l-glutamine, isoleucine, leucine and valine.
- Incorporate a stress reduction regime into your diet
- Take cinnamon. There's evidence that half a teaspoon a day of this common spice improves glucose control in diabetics (Diabetes Care, 2003; 26: 3215-8).