Why are we getting fatter?
Around the globe we are growing in size. As our weight spirals out of control, diets that used to work now don’t seem to work. We go on a diet, lose weight and gain it all back (and more). So, what is to blame for all this obesity?
Understanding Hormones: The Lock and Key Mechanism
Understanding the role that our hormones play is key to gaining insight into their role in weight gain. When we go on that diet, after a bit our metabolism slows because our bodies think we need to slow down because there is less food. With less food, our hormones begin to take over and signal us to eat more. “Please,” our brains say, “we are hungry.” Dr. Fung explains this in terms of our body set weight thermostat. Just like in our homes where we may like the ambient room temperature set at 72 degrees. The heat or cool air will kick in to keep it at 72 degrees, the same goes for our body. It likes to be at a “set weight.” We can diet and lose weight, but we will go back to our “set weight” after a period of time.
Think of hormones as messengers that hold the key to a target cell. Insulin (a hormone), is the messenger or the “key” that helps unlock the receptors (the lock) that let glucose “in” from the blood and into the cells.
We sit down for our evening meal and the food we eat is broken down into fat, protein, carbohydrates and fiber. It is important to note that everything on the menu that we eat has various effects on insulin and glucose.
- Fats break down into fatty acids and minimally raise both blood sugar and insulin levels.
- Carbohydrates are chains of sugar and are broken down into smaller sugars. Carbohydrates raise blood sugar more than other foods and stimulates insulin release.
- Protein breaks down into amino acids and like fat minimally raises insulin levels, and its effect on blood sugar is also relatively minimal.
- Dietary Fiber is not broken down, or absorbed it just leave the building, so to speak.
Don’t shoot the messenger
Insulin is one of the hormones that promotes fat accumulation and storage and helps move glucose into cells. When we eat, ingested carbohydrates are broken down to glucose. In response to rising glucose, our insulin level rises which allows glucose to go from the blood into the cells for metabolism and storage. Glucose is turned into glycogen in the liver. This is called glyconeogenesis, or the creation of glycogen. Glycogen and glucose are easily converted back and forth as needed for energy. Glycogen is the main storage substance for glucose reserves as needed by the body.
Dr. Fung (
Fat is like the money in your savings account; not as easily accessible as your cash. You want money in your wallet, so you don’t have to go to the bank and get money from your savings account. This is like your body, you use up your glucose from glycogen (the money in your wallet) and instead of dipping into your fat stores (your savings account), your brain tells you that you’re still hungry and you eat more – thus replenishing your glycogen stores or putting the money into your wallet – without ever touching your fat stores (savings account).
The fat stores in your belly and is still there for a rainy day because you keep letting your brain tell you to eat.
What does the liver have to do with it?
The liver, however, only has so much room to store glycogen and so when too many carbohydrates have been ingested, the liver will instead convert glucose into fat via a process called de novo lipogenesis, or to create new fat. This fat is deposited in your liver and will lead to a fatty liver similar to what is seen in alcoholism.
Several hours after you have had your meal the blood sugar and insulin levels begin to drop. If you don’t eat at night and let yourself rest, the liver will start breaking down the glycogen into glucose and release it into your body for energy. And if you don’t eat for a period of time (a short fast), your body still has plenty of glycogen. Your body will not run out energy. If you fast longer, say you don’t eat all day, your body will shift its metabolism to free fatty acids in your fat stores (in the liver and other tissues). Thus, you could lose weight because the fat stores are being depleted. You actually can go quite a period of time without eating (we will talk more about that in Part III). Your brain may tell you need to eat, but your body doesn’t really need it.
Let’s stop here for the obligatory disclosures – this is informational ONLY and in no way should be taken as medical advice or a meal strategy. Always seek advice from your trusted healthcare professionals.
To explain the circle – You eat, insulin is released, sugar and fat begin to be stored. You stop eating, your insulin levels fall, and sugar and fat is burned for energy.
Why are things different today?
What is different today as compared to earlier generations? In the “old days,” we ate a small modest breakfast (toast, coffee maybe an egg), a sandwich and fruit for lunch (giant chocolate chips cookies were not yet introduced) and an early dinner. That all occurred in about a 12-hour span. Nighttime came, we stopped eating for those 12 hours and then it stated all over again. Today, we graze all through the day, stop at the drive-thru and eat fast food in our car. We also eat well into the evening (those snacks while we are watching TV). Don’t forget those supersized cookies we had in the afternoon. We now have the luxury of having our food items pre-packaged and loaded with additives. Do you take the time to read the labels?
The Role of Insulin
People who are obese will secrete much higher levels of insulin than those who have a more normal weight. These levels remain high long after a meal has been eaten. High levels will correlate to a higher waist/hip circumference ratio.
Fasting insulin levels
Today, more and more people are being diagnosed with Type II Diabetes. It was only in 1988 that metabolic syndrome (or insulin resistance) was formally described by Gerald Reaven, Emeritus Professor of Medicine at Stanford. He described how adipose tissue, skeletal muscle and liver became resistant to the effects of insulin. This resistance leads to increase blood sugar and the secretion of more insulin occurs until the pancreas can no longer respond and Type II diabetes develops. He described the effect on other organs as “innocent bystanders” of this hyperinsulinemia state, which leads to the comorbidities frequently seen with obesity.
The Role of Cortisol
Have you ever taken prednisone (a synthetic version of the human hormone cortisol)? It is often prescribed for allergic reactions, worsening asthma, back and joint issues, etc. When you took it, did you notice that you were HUNGRY and you ate more? Prolonged use of steroids will raise glucose levels and insulin levels, and you will gain weight. The good news is when you stop taking it, you should lose the weight.
Your stress hormone, cortisol is responsible for the flight or fight response that once was needed in the case of being stalked by a lion or other predator. This is great to have if you have a predator chasing you, but the stress we usually have today is worries about work, children, spouses and to make things worse, we are also not getting enough sleep. With prolonged stress, our glucose continues to be elevated long term, which then triggers the release of insulin. And with that release of insulin, body weight increases, and the waist grows. We’ve all heard that stress makes us gain weight – and indeed it does.
Sleep deprivation stimulates cortisol production. So the less sleep you get, the more your cortisol and insulin levels are elevated. If you want to lose weight, don’t lose sleep about it – just get more sleep.
In Part III, we will tie this all together.
Jason Fung, The Obesity Code, 2016
David Haslam & Fiona Haslam, Fat, Gluttony and Sloth: Obesity in Literature, Art and Medicine, 2009 (ch 2)