Study: How Quickly Your Blood Sugar Falls After Eating Is a Key to Weight Gain

|Updated Apr 13, 2021
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A new study shows that how you metabolize calories determines whether you get hungry within just a few hours of eating, according to a new study just released in the journal Nature Metabolism. Âre you a big dipper or a little dipper? Meaning does your blood sugar fall like a rock, or stay steady? The answer may reveal why some of us might be driven to eat more than others, especially within hours of having our last meal, causing us to be more prone to gain weight or not be able to lose it.

A big dipper is someone whose blood sugar dips shortly after eating, so they feel hungry all over again, even if their cells are adequately fed. A little dipper keeps their blood sugar from dropping so fast or far, meaning their body gets the message: All good here. No reason to eat again for hours, so they end up not overeating throughout the day.

This is significant for anyone trying to lose weight since scientists discovered that a big dip just 2 to 3 hours after eating causes the big dippers to eat 200-300 extra calories a day, which could translate into 20 extra pounds a year.

Knowing whether you’re a big dipper or little dipper could be helpful in adjusting your intake, eating more high-fiber foods (which release energy slowly, preventing big spikes and dips in blood sugar), and helping you regulate appetite and consumption–and ultimately your weight.

The new study tells people why they are hungrier

New research from PREDICT, the largest ongoing nutritional research program in the world that looks at responses to food in real-life settings, show that people who experience big dips in blood sugar levels, within hours after eating, feel hungrier and end up consuming hundreds of more calories during the day than others.

The study followed more than 1,000 individuals, gathering data about their blood sugar in response to meals, and their hunger level over two weeks of eating "free choice" standardized meals.

The biggest variations in blood sugar took place in response to different foods.  Study subjects 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’).

While your genetics and biology may determine who is a big dipper and who is a little dipper, choices in foods and activity levels had an even bigger impact on blood sugar fluctuations.

So even if you are a born big dipper, eating foods high in fiber and low in simple sugar can help regulate blood sugar, as can activity levels throughout the day. The more active you are, the more likely you will burn off the energy before it can cause a surge that allows your body to store the extra calories as fat since by going for that walk, run, or bike ride you'll burn it off.

In the study, “Postprandial glycaemic dips predict appetite and energy intake in healthy individuals,” the research team collected detailed data about blood sugar responses and other markers of health from 1,070 people after eating standardized breakfasts and freely chosen meals over a two week period, adding up to more than 8,000 breakfasts and 70,000 meals in total.

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 stick-on continuous glucose monitors to measure their blood sugar levels over the two-week duration of the study. 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. Prior studies had focused on blood sugar surges, but this study focused on blood sugar dips and reported feelings of hunger.

Understanding your metabolism is the first step

“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," says Dr. Sarah Berry from King’s College London, who was involved in the study. "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.”

Big dippers experienced a 9% increase in hunger and waited around half an hour less to eat again, on average, compared with little dippers, who went longer before needing to eat again, even though they ate the same meals initially.
Big dippers also took in 75 more calories in the 3-4 hours after breakfast and around 312 calories more over the course of the day than little dippers. This kind of pattern could potentially turn into 20 pounds of weight gain over a year, according to the authors.
“Many people struggle to lose weight and keep it off, and just a few hundred extra calories every day can add up to several pounds of weight gain over a year," says Professor Ana Valdes from the School of Medicine at the University of Nottingham, who led the study. "Our discovery that the size of sugar dips after eating has such a big impact on hunger and appetite has great potential for helping people understand and control their weight and long-term health.”

What determines whether you are a big dipper or a little dipper?

In determining who is a big or little dipper, there were no obvious clues, according to the researchers. They found no correlation between age, body weight, or BMI and whether someone is a big or little dipper, although males had slightly larger dips on average than females did. This is in keeping with previous findings that showed that even identical twins can have different responses to the same food.

A whole food plant-based diet with high fiber foods (vegetables, fruit, nuts, seeds, and whole grains) will help keep blood sugar levels steady compared to a diet full of added sugar and simple carbs, studies have found.

The study was conducted by members of the research team at health science company ZOE, composed of scientists from Harvard Medical School, Harvard T.H. Chan School of Public Health, Massachusetts General Hospital, the University of Nottingham, King’s College London, Leeds University, and Lund University in Sweden. They found that when people struggle to lose weight, it can help individuals to understand their metabolism. Tim Spector, Professor of Genetic Epidemiology at King’s College London and scientific co-founder of ZOE, which conducted of the study, adds, “Food is complex and humans are complicated, but our research is finally starting to open up the black box between diet and health."