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The Hunger Hormones, by Dr Libby

The Hunger Hormones, by Dr Libby

The following article is written by Dr Libby Weaver and taken direct from her website.



"Every day of my working life I meet women who are convinced that if only they could get a handle on their appetite then surely everything would be okay. They believe that their body shape and size are completely governed by the calories they eat and the energy they expend. As a result they face a daily battle about what to eat and how much time they devote to exercise. For those of you who read my column regularly, you will have heard me bark on about this being only one piece of the body shape and size equation. Yet there are numerous additional hormonal and emotional factors which contribute.

Of course willpower can play a part; I am not denying its role in food choices and appetite regulation. However, it can also be the over-production of the hormone insulin – whatever the reason, be it food, stress, caffeine (see below) that can interfere with the appetite-regulating messages of another hormone, leptin. So it is important to understand the role of insulin and leptin – and their relationship to each other – if we want to get to grips with our appetite and weight loss challenges.

Insulin and leptin

Over the past 30 or so years, what has become known as the ‘obesity epidemic’ has unfolded. Too many people tend to judge others and assume that overweight people must eat too much and move very little. I have met thousands of people for whom this is just not true.

Some excellent research is being done about the physiology of the human body which explains why some people gain weight regardless of how little they eat or how much exercise they do. Our biochemistry has what are called built-in negative feedback mechanisms that are supposed to stop us from gaining too much weight. We now know that in some people this is not working efficiently or, if it is, it is biochemically being ignored. And research has uncovered what is getting in the way of signals that are supposed to tell our body to eat less and move more. The block is insulin. Insulin’s job is to store energy and, in a world where processed carbohydrates are plentiful, thanks to insulin’s energy-storing role, we gain weight.

Insulin, which is made by the pancreas, moves glucose from our carbohydrate foods out of the blood and into the muscles and fat cells, which results in the weight increase. Even though insulin levels are high, another hormone – leptin – is supposed to kick in and tell your brain that you’ve eaten. Leptin is produced by fat in the fat cells, and it circulates through the blood and binds to receptors in the hypothalamus, the area of the brain that controls energy balance. Leptin is supposed to turn off the desire to eat. In addition to this, it also starts to involve a part of the nervous system called the autonomic nervous system (ANS), various parts of which either promote or block fat burning.

Through research that suppressed insulin with a drug, it has been shown that when insulin levels are lower, leptin can do its job; when they are too high, this interferes with leptin’s ability to signal to the brain to stop eating. Studies that gave leptin to obese people with the hypothesis that it would shut off appetite have usually found that it is not the miracle pill it was anticipated to be. It appears that insulin stops the brain from being able to “see” leptin, which leaves leptin lousy at downregulating appetite. The key here is that insulin levels must first come down for appetite to decrease – especially the desire for carbohydrates, and for weight loss to be sustained.


So what can lead to elevated insulin?

There are numerous processes that can lead to high insulin levels, which in turn can inhibit the appetite-regulating functions of leptin. These include:

1. Too much total carbohydrate consistently consumed at any one meal

2. Too much caffeine driving the release of stored glucose due to the rush of adrenalin

3. Chronic stress. Too much cortisol, our long-term stress hormone, leads to insulin resistance – ie, it prevents insulin from being utilised effectively by the body.

4. Constant activation of an aspect of the autonomic nervous system, either by real or perceived stress (the body sees these as the same), that leads to the constant desire for carbohydrate-based foods, either sweet or starchy


Resistance exercise


Resistance exercise is essential and the best “drug” of all for dealing with insulin. We are crazy if we think exercise only works through burning calories. Twenty minutes of jogging equals one chocolate chip biscuit. One Big Mac requires three hours of vigorous exercise to “work it off.” The reasons behind the importance of exercise are far beyond burning calories.


Firstly, exercise increases the sensitivity of skeletal muscle to insulin. In other words, exercise makes your muscles more insulin sensitive. Therefore, your pancreas can make less insulin, which leads your levels of insulin to decrease, with the end result of less insulin in your blood to turn sugar into fat. The second reason that movement is important is because, after diaphragmatic breathing, certain types of exercise are the single best “treatment” to lower cortisol, your chronic stress hormone. Cortisol lays down what is known as “bad” visceral fat (cortisol wants your body to lay fat down around the middle so your body will always have energy to survive the period of food deptrivation it believes it is in and to keep you alive) and by reducing it you are decreasing the amount of fat that gets deposited around your middle, and this also inadvertently reduces your food intake.


Food Choices


You can see that food choices can certainly influence insulin levels and it is worth having a blood test for both your blood glucose level and your blood insulin levels if you suspect either are high. However, stress also plays a big part – which is why stress management techniques or, if possible, changing our perceptions of situations can go a long way to regulating our appetites. From a more emotional perspective, I will sometimes help clients explore an “appetite” for something other than food in their lives. When you find yourself rifling through the pantry after you have already eaten, ask yourself “what do I really want?”


So, in summary, when we put on weight it can be down to our food and drink choices. However, when it comes to appetite, it may be the over-production of insulin – whatever drives that (eg food, stress, caffeine) that can interfere with the appetite-regulating messages of leptin.




  • See your GP for a blood glucose and a blood insulin test

  • Eat fewer processed carbohydrates out of packets as these tend to raise blood glucose rapidly requiring the pancreas to release a surge of insulin to deal with the elevation in blood glucose.

  • Drink less caffeine

  • Schedule time to breathe; if you work at a computer, have the statement “take 20 long, slow, deep breaths” pop up on your screen at 3pm each day

  • Do exercise that focuses on breathing, such as tai chi, qi gong, yoga and pilates. Or see a breathing specialist to re-train you to move your diaphragm when you breathe

  • Do regular resistance exercise sessions

  • If you have a lovely life and you are simply stressed because of how much you have to juggle in a day, keep in mind that your to-do list is going to have 80 things on it regardless of whether you approach it with a rush-rush attitude or from a calm, centred awareness of your lovely, yet busy life. Your perception has the power to change anything.



Courtesy of Dr Libby Weaver

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