Why Does Halloween Candy Upset Adult Stomachs?

Halloween is just around the corner, and that’s the perfect time to take a hard look at all the candy, carbs, and sugars associated with the holiday.

This week, we’re going to look at why Halloween candy can be so upsetting to an adult stomach.

When you’re a kid, Halloween means one thing: bags and bags of candy. As a kid, it’s easy to down a pound of the sweet stuff, but most adults would be left with a painful stomach ache the next day. As it turns out, there’s a gene to blame for the onset of adult “candy intolerance.”

Researchers from the Buck Institute of Age Research in California have found the reason why too much sugar can spook an adult’s digestive system. Researchers studied a population of fruit flies and found that the Foxo gene, an insulin transcription responder, turns on and off in younger fruit flies, allowing them to seamlessly adapt to changes in diet.

Older flies, however, aren’t so lucky, and the Foxo gene remains turned on, which disrupts their metabolism. Foxo is found in both flies and humans.

“It was unexpected that a process used to respond to nutritional changes in the young animal becomes deleterious in older animals by being constitutively activated,” says lead researcher Henri Jasper, Ph.D., a professor at the Buck Institute.

Changes in Foxo expression likely occur because of an evolutionary need. Younger organisms require a more adaptable digestive process.

Follow That Candy Bar!

It seems like a cruel gene that would allow kids to eat the sweet stuff but not adults. But in fact, it’s all about the aging digestive system.

After unwrapping a candy bar and taking that first bite (and probably a second, and a third) the sugars in candy go through a dramatic transformation. The candy is mixed with saliva as you chew, and salivary enzymes begin to break down the sugars into smaller units that are easier for your body to digest, according to the American Journal of Clinical Nutrition.

From there, the candy travels down to the stomach through the esophagus and gastric acid takes over, breaking sugars down even further and hydrating them with water to increase bulk and mobility.

At this point, your candy bar has been transformed into chyme. This slurry of different substances is pushed along through the stomach and out of the pyloric sphincter into the small intestine. Here, most sugars are broken down and absorbed into various parts of the body through a series of transporter systems. Insulin, which is a glucose transporter, is greatly affected by the activity of the Foxo gene.

Insulin Resistance and Diabetes

“Insulin resistance, which results in constitutive Foxo activation, occurs in many tissues of old humans,” Jasper says. “This results in the age-associated increase in the incidence of type 2 diabetes, and it is likely that chronic Foxo activation in intestinal cells also results in metabolic dysfunction in humans.”

Glucose (a simple sugar, or monosaccharide) is the culprit in insulin disorders like diabetes. It is largely absorbed in the small intestine. Glucose is the body’s main fuel source, and when its absorption and regulation is off-kilter, weight gain, inflammation, and a whole host of health horrors can arise.

“[It’s] important to explore why Foxo is continuously activated in old guts. We suspect that environmental stressors—oxidative stress, infection, cell damage—play a role,” Jasper says.

So this Halloween, go out and enjoy the night with the goblins and ghouls, but keep the candy in the bowl for those with younger guts.

Jasper recommends an alternative for those of us with less adaptable guts: “Have fun, but eat lots of fruits and nuts instead of candy.”

  • Coreina Spencer
    Posted at 22:42h, 05 January


  • Tammy Mershon
    Posted at 01:41h, 30 November

    Great information.

  • Harrison H. Ross
    Posted at 17:26h, 23 November

    I guess that’s one of the things that sucks getting older. Very informative!

  • Billie Ridinger
    Posted at 18:06h, 21 November

    Great read

  • Luz Laminoza
    Posted at 18:52h, 19 November


  • Curti skipwith
    Posted at 18:31h, 17 November

    SEE…for years I loved Halloween…but now..not so much…gezz… a holiday where free candy is given away…and I can no longer join in…booo

  • Curti skipwith
    Posted at 18:30h, 17 November

    SEE…for years I loved Halloween…but now..not so much…gezz… a holiday where free candy is given away…and I can no longer join in…booo

  • Robert T Lucas
    Posted at 16:13h, 17 November

    Great info thanks

  • Graciela Esquivel
    Posted at 03:54h, 12 November

    awesome information

  • Annais Ramirez-Velazquez
    Posted at 19:28h, 07 November

    That is great to know.

  • Cheryl Grose
    Posted at 18:13h, 06 November

    Great information

  • Cheryl Grose
    Posted at 18:10h, 06 November

    Good article

  • Ronald E Scholz
    Posted at 15:55h, 06 November

    Interesting to know we share a gene with flies.

  • Terrance Mcgee
    Posted at 15:50h, 06 November

    Thank you for this information.

  • Elisabeth Beinecke
    Posted at 15:13h, 06 November

    great read thank you

1 18 19 20