How hypothyroidism/insulin resistance affect weight loss

Many hypothyroid patients struggle with a difficulty to lose weight. At first, if you'd gained weight before your thyroid problem is diagnosed, you were probably told you'd be able to lose it more easily -- or perhaps you were even told you'd lose all the extra weight -- once you started on your thyroid hormone replacement. So you take your thyroid hormone, and the weight doesn't come off.
Later, despite "normal" TSH levels, and lower-calorie, low-fat diets and exercise, you find yourself still gaining, or not losing weight. You may also have high cholesterol levels. The doctor then tells you that your weight problem doesn't have anything to do with your thyroid. Many folks I've spoken with have told me that they were on extremely low calorie diets, exercising 2-3 hours a day, and they still were not losing weight.
What thyroid patients need to know more about are three factors that are likely at work for many of us with a difficulty losing weight -- a changed metabolic "set point," changes in brain chemistry due to illness and stress, and insulin resistance. But first, you need to determine if your hypothyroidism is undertreated. Once you've made sure that your thyroid treatment is optimal according to you and your doctor, then there's still a number of essential things you need to know in order to lose weight.

Metabolic Set Point
According to Dr. Lou Aronne, author of the best-selling Weigh Less Live Longer, when you begin to take in too many calories, you have a small weight gain. Then, in order to maintain your set point weight, "your metabolism speeds up to process the excess calories, your appetite decreases, and some of the newly gained weight drops off." He calls this metabolic resistance.
Dr. Aronne believes that every person's body has what is called a weight "set point." Just like your body works to maintain a temperature "set point" of 98.6, it also appears to work toward maintaining a particular weight "set point."
His theory is that in people with a chronic weight problem, the body puts up only modest metabolic resistance to weight gain. If you continue to take in more calories than you burn, the metabolic resistance loses strength, and your body then establishes a new, higher weight set point.
Dr. Aronne believes you can't completely eliminate the metabolic resistance, but a slow steady approach to dieting helps to minimize it. Also, a key way to increase metabolism is through exercise.
 

Changes in Brain Chemistry
Hunger is intricately tied to your brain chemistry. According to Dr. Aronne, your hypothalamus senses you need energy, and issues the brain neurotransmitter neuropeptide Y (NPY) with the message "eat carbohydrates." The surge of NPY is what you experience as "hunger," Once the hypothalamus senses you've eaten enough carbohydrates, it releases serotonin to tell the body, "enough carbohydrates."
But this system can be dramatically altered by several factors, all of which can be present in chronic thyroid disease: Your metabolism is too slow for the appetite level set by your brain. Your body is under stress, which interferes with the neurotransmitter functions, and is known to reduce the release of serotonin. In fact, part of the success of the recently recalled diet drugs fen-phen was the fact that they increase serotonin and create a "feeling of fullness."

 
Insulin Resistance
Insulin is a hormone released by the pancreas. When you eat foods that contain carbohydrates (which make up the majority of most of our diets), your body converts the carbohydrates into simple sugars. These sugars enter the blood, becoming "blood sugar." Your pancreas then releases insulin to stimulate the cells to take in the blood sugar and store it as an energy reserve, returning blood sugar levels to a normal level.
Carbohydrates can be "simple," high-glycemic carbohydrates such as pasta, bread, sugar, white flour and cakes, or "complex" lower-glycemic carbohydrates, like vegetables and whole grains.
Insulin resistance means that cells have become less responsive to the effects of insulin. So your body has to produce more and more insulin in order to maintain normal blood sugar levels. The insulin can also remain in your blood in higher concentrations. This is known as hyperinsulinemia.
In addition to those who seem to have a lowered need for carbohydrates, some people simply eat too many carbohydrates. Today's low-fat diets emphasize more and more pasta, bagels, Snackwells, and sugary fat-free products, and most of these are high-glycemic carbohydrates. Basic over-consumption of high-glycemic foods carbohydrates can also trigger insulin resistance and overweight.
If you are insulin resistant, eating carbohydrates can make you crave more carbohydrates. You'll gain weight more easily, and have difficulty losing it. It is estimated that 25 percent of the general population -- and 75 percent of overweight people -- are insulin resistant.
High insulin levels can stimulate your appetite, making you feel even hungrier than normal for carbohydrate rich food, while lowering the amount of sugar your body burns as energy, and making your cells even better at storing fat, and even worse at removing fat.
When you're creating this excess insulin, it also prevents your body from using its stored fat for energy. Hence, your insulin response to excess carbos causes you to gain weight, or you cannot lose weight.
The weight problems are not the worst aspect of insulin resistance. Insulin resistance may set up a whole syndrome of other serious health problems. For example, insulin resistance and hyperinsulinemia, which tend to go together, are often precursors of diabetes. And insulin resistance is also associated with a substantially increased risk of coronary artery disease, high blood pressure, and high cholesterol.
 
Insulin Resistance and Thyroid Disease
It seems likely that hypothyroidism, with its penchant for slowing down everything else in our systems right down to our cells, slows down our body's ability to process carbohydrates and our cell's ability to absorb blood sugar. Hence, the carbohydrates we could eat pre-thyroid problems now are too much for our systems to handle. So excess carbohydrates equals excess insulin equals excess weight. Plus, the fun side effects of blood sugar swings (tiredness, dizziness, fatigue, exhaustion, hunger, etc.) that we may be mistaking as thyroid symptoms and our doctors say can't possibly be.
Any illness -- such as the chronic thyroid problems we all face -- also creates physical stress. And stress raises cortisol levels. And increased cortisol increases insulin levels. (I know my cortisol was through the roof last time the doctor checked. She had no idea why.) More insulin means increased chance of insulin resistance.
There's also a vicious circle aspect to this. The liver mediates between the activities of the insulin-releasing pancreas and the adrenal and thyroid glands, which are supposed to "tell" the liver to release glucose. If the adrenals and thyroid aren't working properly on the "telling" end, or if the liver is sluggish, stressed out, or toxic, and not working on the "receiving" end, the system goes out of balance. Either way, the result is elevated excess insulin.
And ultimately, if your adrenal glands are stronger than your pancreas, this can potentially lead to diabetes. If your pancreas is the stronger organ, which is more common, then you get fatigue, lowered body temperature, and low blood sugar (hypoglycemia).
All these factors mean that insulin resistance is probably even more of a factor for overweight people with hypothyroidism than for the general population.
 Low intensity, prolonged exercise can substantially reduce insulin levels.
How to Lose Weight and Fight Insulin Resistance
Weight loss is the most important method of eliminating insulin resistance. So it's one of those chicken and egg situations. The less you weigh, the less insulin resistant you will be. But insulin resistance makes it difficult to lose weight.
So, for people who are insulin resistant, one of the only effective methods is by eating a low fat, low carbohydrate, protein sufficient diet. This means that in addition to the usual restrictions of a low-fat diet, you also need to seriously limit intake of sugar and starches, cutting back on pasta, rice, potatoes, white flour breads, cereal, corn, peas, sweet potatoes, desserts, dairy products, meats, and fruit with a high sugar content.
You may feel frustrated that there's nothing left to eat. But you need to rethink your eating habits, shifting to a diet of chicken, turkey, fish, non-starchy vegetables, legumes, and certain grains. And for those who are insulin resistant, once you start eating this way, you'll find it easier, as your carbohydrate cravings will subside dramatically.
Exercise is probably the best medication on the market to treat insulin resistance syndrome.