Noon, and the office crowd pours into the street. A plate of cơm tấm sườn (broken rice with grilled pork chop), plus a bubble tea for "energy."
2pm, and the computer screen starts to blur. Eyelids droop, yawns keep coming. By 4pm your stomach is growling again, and your thumb is already opening the snack delivery app.
Sound familiar? Part of this story has to do with what scientists call a glucose spike after eating. The rest is more interesting than you'd think.
In this article
Blood sugar rising and falling after a meal is normal
First, don't worry. Blood sugar rising after you eat is completely normal. It's how your body takes in energy.
Here's the journey:
- When fasting, a healthy person's blood sugar usually sits around 4 to 5.5 mmol/L.
- After eating, starch and sugar are broken into glucose and enter the blood. Blood sugar rises, usually peaking after about 30 to 60 minutes.
- Insulin is called in. It's like a doorkeeper letting glucose into your cells.
- After about 2 to 3 hours, blood sugar returns close to where it started.
A gentle curve up and back down like this is healthy. What scientists are interested in is when that curve rises too sharply and then drops too low.
The crash after the spike, and the 4pm hunger
When a meal sends a lot of glucose into the blood very fast, the body responds by releasing a lot of insulin. Sometimes so much that, a few hours later, blood sugar drops lower than it was before the meal.
A 2021 study of more than 1,000 healthy people in the UK and US tracked this. People with deep "dips" after breakfast tended to:
- Feel hungry sooner.
- Eat their next meal earlier.
- Eat more calories over the day.
It's an intriguing finding, but it needs more research to be fully understood. And everyone responds very differently.
And that 2pm drowsiness? We'll be honest: blood sugar is only part of it. The human body clock naturally has a "dip" in alertness in the early afternoon. A big meal and a short night's sleep also play a role. So don't pin it all on the bowl of rice.
What makes a spike bigger?
For the same person and the same calories, blood sugar can rise very differently depending on the meal:
- Sweet drinks. Bubble tea, soda and juice hit the blood very fast because there's no chewing and nothing to slow them down.
- Soft, mushy starch. Plain rice porridge, white bread and overcooked rice rise faster.
- Starch on its own. A plain baguette, a plate of sticky rice with nothing alongside.
- Sweets on an empty stomach. A slice of cake at 4pm when your stomach is empty.
- Sitting still after eating. Muscles that aren't working use less glucose.
A large 2015 study in Israel also showed that the same food produces different curves in different people. Some spike on bananas but not on cookies, and others the opposite. So there's no one formula for everyone.
Four small tips, no need to give up rice
The good news: a few simple habits help smooth the curve. No cutting starch, no changing your menu.
1. Vegetables and protein first, rice after. Several small studies show that with the same meal, eating vegetables and meat or fish about 10 minutes before the rice leads to a lower blood sugar rise than eating the rice first. Fiber and protein slow down digestion, so glucose enters the blood more gradually.
2. Get enough protein and fiber at every meal. In a plate of cơm tấm, the grilled pork is the protein; add cucumber, tomato and đồ chua (pickled carrot and daikon) for vegetables. Swap the bubble tea for unsweetened iced tea and your lunch is already much gentler.
3. Walk for 10 to 15 minutes after eating. A 2022 review of many studies found that simply getting up for a light walk after a meal helps keep blood sugar lower than sitting still.
4. Have sweets at the end of a meal, not on an empty stomach. If you're craving cake, have it right after your main meal. By then your stomach has vegetables, protein and fat as a "cushion," so the spike is milder.
No need to do all four at once. Pick the easiest one for you and stick with it for a week.
Do you need a continuous glucose monitor?
Recently, continuous glucose monitors (CGMs), the little patches worn on the arm, have become popular. Many healthy people try one to see their own curves.
It can make you curious and help you understand your body. But keep a few things in mind:
- In healthy people, blood sugar rising and falling after eating is normal. A high peak after lunch doesn't mean something is wrong.
- Scientists are still studying what spikes in healthy people mean in the long run.
- Watching the numbers too closely can turn eating into a source of stress.
If you have a health condition related to blood sugar, any monitoring should be done together with your healthcare provider.
Inside the kOBE kitchen
The principle of "enough protein, enough vegetables, moderate starch" is how kOBE's ready meals are put together.
For example, our 350g Chicken Kale Namul Poke has 379 kcal and 29g of protein, with kale, chicken breast and starch in one bowl and a sauce based on Lean Mayo. Our frozen rice bowls also come with a main dish and Sesame Kale, with sauces cooked with monk fruit sweetener.
A small tip while eating: have a few bites of kale and chicken first, then move on to the rice.
If you'd like to build your own meal at home, the ready-cooked ingredients on our Ingredients page, such as Sous Vide Chicken Breast, Sesame Kale and Red Brown Rice, all list calories, protein and carbs clearly.
Frequently asked questions
Should healthy people worry about blood sugar spikes?
Does eating fruit cause a spike?
Is it better to eat rice first or vegetables first?
Is feeling sleepy after eating caused by blood sugar?
Keep reading
Sources
- Wyatt P. et al. (2021). Postprandial glycaemic dips predict appetite and energy intake in healthy individuals. Nature Metabolism 3:523 to 529.
- Zeevi D. et al. (2015). Personalized nutrition by prediction of glycemic responses. Cell 163(5):1079 to 1094.
- Shukla A.P. et al. (2015). Food order has a significant impact on postprandial glucose and insulin levels. Diabetes Care 38(7):e98 to e99.
- Buffey A.J. et al. (2022). Systematic review and meta-analysis on breaking up prolonged sitting with standing or light walking. Sports Medicine.
- Further reading: Understanding Nutrition 16th ed., chapter 4.
