It's not your fault you're hungry all the time: Our groundbreaking new study reveals why

April 12, 2021

If you’re feeling hungry all the time and struggling to lose weight, the answer may lie in how your body is responding to the foods you’re eating.

New results from our research, published today in the prestigious medical journal Nature Metabolism, show that ‘big dippers’ - people who experience big dips in blood sugar levels several hours after eating - end up feeling hungrier and eating hundreds more calories during the day than ‘little dippers’ whose responses are smaller.

Our findings help to explain why some people struggle to lose weight, even on calorie-controlled diets, and highlight the importance of understanding each person’s unique biology when it comes to diet and health.

Here’s what these findings mean for you and your health.

Get the low-down on sugar dips

  • More than 1,000 people took part in our study, which gathered detailed data about blood sugar responses and hunger after eating.
  • We found big variations between individuals in how their blood sugar levels respond to various foods.
  • People whose blood sugar levels dip significantly 2-4 hours after eating (‘big dippers’) are more likely to feel hungry sooner and consume an average of around 300 more calories over the course of the day than people with the smallest dips (‘little dippers’).
  • Whether you’re a big or little dipper is likely to be a combination of your unique biology, meal choices and activity levels.
  • Previous studies have only looked at how blood sugar rises and falls in the first two hours after eating affect hunger (blood sugar peaks), not the dips afterwards.
  • Choosing foods that work together with your unique biology could help you feel fuller for longer and eat less overall.
  • Our ZOE test can help you discover your unique metabolism and gut microbiome, with personalized advice on foods that work best for your body.

Studying sugar dips

Led by data scientists here at ZOE and our collaborators at King’s College London, the research team collected detailed data from 1,070 people after eating more than 70,000 standardized breakfasts and freely chosen meals over a two week period. 

The standard breakfasts were based on muffins containing the same amount of calories but varying in composition in terms of carbohydrates, protein, fat and fiber. Participants also carried out a fasting blood sugar response test (oral glucose tolerance test), to measure how well their body processes sugar.

Participants wore continuous glucose monitors (CGMs) to measure their blood sugar levels over the entire duration of the study, as well as a wearable device to monitor activity and sleep. 

The research team also asked people to record their levels of hunger and alertness using a phone app, along with exactly when and what they ate over the day.

Bigger blood sugar dips lead to feeling hungry and eating more

Previous studies looking at blood sugar and hunger after eating have focused on the way that levels rise and fall in the first two hours after a meal, known as a blood sugar peak.

After analyzing all the data, we noticed that some people experienced significant ‘sugar dips’ 2-4 hours after this initial peak, where their blood sugar levels fell rapidly below baseline before coming back up. 

These ‘big dippers’ had a 9% increase in hunger and waited around half an hour less before their next meal than ‘little dippers’ who didn’t have a pronounced sugar dip, even though they ate exactly the same meals. 

Big dippers also ate 75 more calories in the 3-4 hours after breakfast and around 312 calories more over the whole day than little dippers. This kind of eating pattern could potentially add up to many pounds of weight gain over a year. 

What makes you a big or little dipper?

We saw big variations in blood sugar responses between people after eating exactly the same meals, but we couldn’t find a correlation between age, bodyweight or BMI and being a big or little dipper, although males had slightly larger dips than females on average. 

This fits with previous findings from PREDICT showing that even identical twins can have different responses to the same foods.

There was also some variability in the size of the dips experienced by each person in response to eating the same meals on different days. 

This tells us that whether you’re a big or little dipper comes down to a combination of your unique metabolism together with the day-to-day effects of the foods you choose and your activity levels.

How can you find out if you’re a ‘big dipper’?

Food is complex and humans are complicated, but our research is finally starting to open up the black box between diet and health. 

We’re excited to have been able to turn this cutting-edge science into an at-home nutrition and microbiome test so that everyone has the opportunity to discover their unique responses to food to best support their metabolism and gut health.

Our ZOE at-home test and program can help you understand your own blood sugar responses to any food, and provides personalized advice on the best foods to eat to take back control of your health and weight. 

Discover your unique biology

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