#39 Why am I Still so Hungry after Bariatric Surgery?

HOST: Registered Dietitian Nutritionist Dr. Susan Mitchell 

The one thing about science is that it’s constantly changing. That’s a good thing as research teaches us more and more, but it can be frustrating too. I remember as a young dietitian my Dad had been put on a heart healthy diet which, at the time, severely restricted eggs. This was before we knew that it was the total saturated fat in our diet that was more important than the cholesterol in an egg. I remember trying to share this new research and diet changes with my Dad who wouldn’t hear of it. He had been told one way and that’s the way it was. After all what did I know, I was just his baby girl.

Throughout the pandemic, you’ve no doubt heard that the science keeps evolving as we learn more about the virus. Well it keeps evolving in the field of nutrition and obesity medicine too. And some of what we’re finding out gives us new insight into that dreaded weight regain after significant weight loss and after bariatric surgery. 

Obesity has always been considered an outcome of eating too much. So much ugly goes with that idea such as weight bias, shaming, bullying or the assumption of a lack of self control. Sure your genes, the environment and the amount of calories eaten do all play a role. In fact, the intake of macronutrients like protein and carbs can affect the production of neurotransmitters or brain chemicals like dopamine and serotonin that then affect appetite. The amount of protein and carbs that you eat are important but should not be the only focus. New research suggests that perhaps overeating does not cause obesity. Overeating does not cause obesity but rather the disease of obesity causes overeating. Let me repeat that… overeating does not cause obesity… but rather the disease of obesity causes overeating. Research suggests that obesity is a disease and should be treated that way. It’s a disease that causes a malfunction or dysfunction from the medical view point in the regulation of your appetite and it’s connected to the brain.

New emerging research suggests that signals which physically tell us we’re hungry or we’re full are controlled by your brain. It appears that the brain is not only involved in regulating hunger and feeling full but also with eating for pleasure or what’s called hedonic eating. Hormone regulation is controlled by the brain and this hormone regulation plays a large part in appetite control. In obesity, there seems to be a malfunction in these signals that the brain’s sending out.

Maybe you’ve heard of hormones called leptin and ghrelin? When your stomach is full, the brain signals for the release of leptin as a appetite control. In obesity, this signaling has its wires crossed and is not working correctly. This may lead to being hungry and overeating when you’re actually full. The hormone ghrelin is tied to stimulating the desire to eat and it may work overtime. (Let me mention that one of the benefits, at least short term, of sleeve gastrectomy is a decrease in the production of ghrelin due to the removal of a significant part of the stomach resulting in a decrease in appetite.) And guess what happens as a result of these messed up signals? You never feel satisfied and feel that constant hunger. Don’t miss this as it’s really important to know. When you lose significant weight as you have thru surgery, the opposite of what you think should happen often does. You think you should feel full and not as hungry but that malfunctioning signal that tells you that you are full isn’t doing it’s job and the hunger hormone ghrelin often increases. No wonder you’re frustrated but now you and we as health care providers are beginning to understanding why this may happen.

Additional research suggests that GLP-1 (whose real name is glucogon-like peptide-1) may have an important role in regulating appetite as it can also acts as a hormone. It’s a player too in signaling with the brain whether you’ve had enough to eat or you’re hungry. What’s really interesting is that medications using this GLP-1 may be good news for a malfunctioning appetite. And some of these are on the market now and are used in the treatment of diabetes.

Weight regain is a big issue after significant weight loss and weight loss surgery. It’s not unusual to see weight regain a year down the track following a large loss. Why? One of the reasons may be that the body is releasing more hormones that make you think you’re hungry. When you lose weight, the body will work to regain the weight unless this appetite regulation or signaling starts to function correctly. Don’t get me wrong, behavior change, exercise, healthy eating, realistic portions, and the right percentage of macronutrients like protein and carbohydrate all continue to be important part of your journey. But there are potentially more options in the form of medications that may end up playing a role too and partnering with these others lifestyle changes. Think of it like high blood pressure or diabetes, sometimes lifestyle changes are not enough and medication is needed. When obesity is treated as a disease, it’s the same thought process. Sometimes lifestyle changes are not enough. As we learn more about the many hormones related to weight and how their levels are affected, I can’t wait to see what new developments continue to come forth to work along with behavior changes and nutritional strategies. New developments that will hopefully add additional options to help with weight regain. I’ll keep you posted as I hear more.