Study on Blood Sugar Levels and Hunger

Janet Tiberian Author
By Janet Tiberian, MA, MPH, CHES
July 17, 2021
blood sugar and hunger

Are You Hungry All the Time? You May have Low Blood Sugar

You’re trying to lose weight. But despite your best efforts, it’s not working. One problem is that you’re hungry most of the time, even shortly after eating a meal. Ignoring hunger will make you feel miserable, while giving in can add hundreds of extra calories. You’re stuck between a rock and a hard place. And of course, you’re probably wondering: Why am I hungry all the time?

You’re not alone. Many people struggle with unexplainable hunger, inspiring researchers from King College London to figure out why. Researchers think low blood sugar may be to blame, according to a study published in Nature Metabolism.

Study on Low Blood Sugar Linked to Increase Hunger Pains

This study involved researchers from PREDICT, the largest ongoing nutritional research program in the world. Its team includes researchers from King's College London and ZOE, a health science company composed of researchers from Harvard Medical School, Harvard T.H. Chan School of Public Health, Massachusetts General Hospital, the University of Nottingham, Leeds University, and Lund University (Sweden).  

PREDICT researchers recruited 1,070 study participants and gave each of them a fasting glucose tolerance test to measure how well their body’s processed sugar. Participants also were given continuous glucose monitors, a small sensor that’s subcutaneously inserted and monitors blood sugar levels, as well as wearable devices to track physical activity and sleep. Researchers then followed participants as they ate standard breakfasts, i.e., muffins consistent in calories but varying in macronutrients (carbohydrates, protein, fat and water) along with freely chosen meals for two weeks while participants recorded their hunger levels, alertness and kept a precise food diary via a mobile app. After the two weeks, researchers had collected detailed data on more than 8,000 breakfasts and 70,000 meals in total.

Blood sugar usually ranges between 70 mg/dL to 100 mg/dL. It’s normal for blood sugar levels to rise after meals. After you eat, your body breaks down most of the food into sugar to be used as energy to help muscles and organs (including your brain) work properly. This process triggers the pancreas to release the hormone insulin which “escorts” sugar into cells for use, allowing the blood sugar level to return to normal. But If sugar spikes higher than normal or remains high for a longer than normal period, it can build up in the blood, damaging organs, nerves and blood vessels. Many people don’t realize their blood sugar is high. And if it drops significantly lower than normal (generally 50 mg/dL) for a longer time, it can cause hypoglycemic symptoms such as hunger, dizziness, fatigue, weakness, trembling, sweating and palpitations.

This is why previous blood sugar studies focused on changes in blood sugar levels two hours after eating. However, the new study looked at blood sugar swings between two and four hours after eating. And results found that some participants experienced rapid and significant drops in blood sugar before returning to baseline levels. Researchers referred to this group as “big dippers” and they also had:

  • A nine percent increase in hunger
  • Waited an average of 30 minutes less than participants who had smaller drops in blood sugar (referred to as “little dippers”) before eating their next meal, despite eating the exact same food.
  • Eaten 75 more calories three to four hours after breakfast and a little more than 300 calories throughout the day compared to little dippers, an eating pattern that researchers associated with gaining 20 pounds in a year. 

Researchers attributed variances among participants to physical activity levels and personal metabolic rates. Of course, some participants may have had underlying low blood sugar. 

“There are a few reasons you may be dealing with low blood sugar,” says Bernard Kaminetsky, MD, medical director, MDVIP. “For instance, you may not be getting enough calories into your diet. Or you can have a metabolic issue such as an overactive pancreas, insulin resistance or prediabetes or diabetes.” 

Trying to Lose Weight but Always Hungry, Talk to Your Doctor for Advice. 

If you’re trying to lose weight, work with your primary care physician. They may be able to detect health issues that can interfere with your weight loss efforts. If you don’t have a doctor, consider partnering with MDVIP. Find a physician near you and begin your partnership in health »  

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About the Author
Janet Tiberian Author
Janet Tiberian, MA, MPH, CHES

Janet Tiberian is MDVIP's health educator. She has more than 25 years experience in chronic disease prevention and therapeutic exercise.

View All Posts By Janet Tiberian, MA, MPH, CHES
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