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New Study Explains Why Some People are Always Hungry

New research forms a connection between metabolism and hunger pangs.
FACT CHECKED BY Sydney Greene, MS, RD
hungry man

Have you ever felt hungry just a few hours after engorging in a calorie-rich meal? According to new research, there's a key reason why that's happening—and it has nothing to with your cravings. In fact, your blood sugar levels may be to blame.

A new study from PREDICT (aka the largest ongoing nutritional research program in the world), and led by researchers at King's College London and health science company ZOE, recently published in the journal Nature Metabolism examined why some people struggle to lose weight even when they're following calorie-controlled diets.

For two weeks, researchers collected exhaustive data on blood sugar responses and other markers for health from nearly 1,100 people after they ate standardized breakfasts and meals of their choosing. In total, they examined more than 8,000 breakfasts and 70,000 meals. While the standard breakfasts included muffins containing the same amount of calories, they had varying amounts of protein, carbs, fat, and fiber. (Related: The 7 Healthiest Foods to Eat Right Now)

The participants wore stick-on continuous glucose monitors (CGMs) to measure their blood sugar levels during the two-week period so researchers could see how well their bodies processed sugar. They even wore a device that monitored their levels during the day while they were active and at night while they were sleeping. Finally, participants were asked to record when they felt feelings of hunger and alertness using a phone app in tandem with notes on what and when they ate throughout the day.

While past studies have primarily analyzed fluctuations in blood sugar during the first two hours after a meal, referred to as the blood sugar peak, the team of researchers for this study found significant dips in blood sugar actually occurred within two to four hours after that initial peak. 

Even though they consumed the exact same meals, those who experienced the most significant dips (known as the big dippers) had a 9% increase in hunger and waited about 30 minutes less than little dippers before having their next meal. Big dippers also ate 75 more calories in the three-to-four-hour window after breakfast and an estimated 312 calories more over the course of the day than little dippers. 

"It has long been suspected that blood sugar levels play an important role in controlling hunger, but the results from previous studies have been inconclusive," Dr. Sarah Berry, study author and researcher from King's College in London, said in a statement.

"We've now shown that sugar dips are a better predictor of hunger and subsequent calorie intake than the initial blood sugar peak response after eating, changing how we think about the relationship between blood sugar levels and the food we eat."

The study found no correlation between age, BMI, or body weight between big and little dippers. However, men tended to have slightly larger dips than women. It truly comes down to knowing your own metabolism. Essentially, understanding how your blood sugar levels fluctuate after eating meals can help you choose the foods that will help keep blood sugar levels stable so that you stay full for longer.

For example, if you're someone who likes to eat granola in the morning, but you always find yourself starving by 11:30 a.m., consider opting for foods with a lower glycemic index that won't cause your blood sugar levels to rise and fall as quickly. Low GI breakfast foods include full-fat or Greek yogurt with nuts and fruit, as well as whole wheat tortillas with peanut butter and a sprinkle of raisins.

For more, be sure to check out Foods That Increase Your Diabetes Risk, Says Expert. And to get all the latest news delivered right to your email inbox every day, sign up for our newsletter!

Cheyenne Buckingham
Cheyenne Buckingham is the news editor of Eat This, Not That!, specializing in food and drink coverage, and breaking down the science behind the latest health studies and information. Read more
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