hunger and gut bacteria

“Why am I constantly hungry?” is a question I hear from many of my patients. At best, constant hunger is annoying and distracting; at worst, it’s a sign that something’s amiss. Either way, the mental wrestling can make it hard to trust the messages your body is sending you. Assuming that you’re eating regularly through the day, there are several possible explanations why hunger might be a constant companion.

Your body thinks it’s in a famine

Making sure to include protein in each meal may keep you satisfied longer. That could be eggs, yogurt, tofu, beans, fish, chicken or meat.  (DREAMSTIME)

Your body has biological mechanisms in place to keep your weight from dropping below your set point — the weight range you are genetically predisposed to maintain — whether you are experiencing famine or what just looks like a famine (a.k.a. calorie-restricted dieting). One is a drop in your resting metabolic rate. The other is an increase in appetite.

Even though the body needs fewer calories as weight decreases, hunger and the drive to eat increase. In fact, increases in appetite may play a more important role than a slowing metabolism in weight-loss plateaus. For every 2.2 pounds of weight lost, we burn about 20 to 30 fewer calories per day — even fewer for some people — whereas appetite grows by about 100 calories per day. Basically, it’s easier for your body to protect itself by boosting your appetite — and your calorie intake — than to slow your metabolism and run on fewer calories.

You’re not getting enough protein at meals

Of the three macronutrients — carbohydrates, protein and fat — protein contributes the most to satiety, the feeling that you’ve eaten enough. That doesn’t mean you should go overboard on protein — you need the nutritional variety from all three macronutrients — but making sure to include some protein in each meal and snack may keep you satisfied longer. That could be eggs, yogurt, tofu, beans, fish, chicken or meat. Experiment to see how you feel after eating different meals.

Your gut microbiota isn’t very diverse

Your gut, and the microbes that dwell in it, act as a “mini brain,” influencing, among other things, mood, appetite and food cravings. The tens of trillions of bacteria and other microbes in our gut produce a number of compounds, including some that are identical or similar to appetite hormones. About 20 minutes after a meal, certain bacteria in your gut send signals that you’ve had enough to eat by stimulating the release of a hormone that has been linked to feelings of satiety. But if you don’t have a very diverse microbiota — the microbe population living in our intestines — other species can become dominant, and what they need to survive and thrive may be different from what your body needs.

When you and a dominant group of microbes aren’t on the same page, they will try to manipulate your eating behaviour for their benefit. They may cause cravings for their preferred foods, or for foods that suppress their competitors. They may simply increase your hunger levels until you eventually eat what they want you to eat. Either way, this creates a vicious cycle. For example, if you eat a lot of sugary foods, “sugar-loving” microbes will thrive, whereas microbes that don’t do so well on sugar may weaken or die. Because the sugar-loving microbes are well-nourished, they’ll gain even more influence, increasing sugar cravings.

Support a diverse microbiota by eating foods rich in fibre and probiotic bacteria, being physically active, handling stress and getting adequate sleep. This reduces the chance that any single species will have the numbers to gain an upper hand, and may help reduce food cravings and unusual hunger.