# Feeling Tired after eating fast food **URL:** \ **Category:** Factual Questions\ **Created:** [March 11, 2003, 10:13pm UTC](https://boards.straightdope.com/t/feeling-tired-after-eating-fast-food/160669 "2003-03-11T22:13:20Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![mipiace](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@mipiace](https://boards.straightdope.com/u/mipiace)\ **Post date:** [March 11, 2003, 10:13pm UTC](https://boards.straightdope.com/t/feeling-tired-after-eating-fast-food/160669/1 "2003-03-11T22:13:20Z")
Why is it I feel so tired in the afternoons if I eat fast food for lunch? I feel like my blood sugar is somehow really low but it probably has more to do with fats than anything. This seems to be more of a problem if I have consistently been eating a good diet. The more often I eat those high fat foods, the easier it is to digest. Does your body accumulate a “tolerance” to high fat foods? ---
**Author:** ![scm1001](https://avatars.discourse-cdn.com/v4/letter/s/c4cdca/32.png) [@scm1001](https://boards.straightdope.com/u/scm1001)\ **Post date:** [March 12, 2003, 9:18am UTC](https://boards.straightdope.com/t/feeling-tired-after-eating-fast-food/160669/2 "2003-03-12T09:18:06Z")
I think after a good meal the body naturally wants to rest to digest the meal. This sort of behaviour is common amongst animals and humans. Welcome to siesta time ---
**Author:** ![MissBungle](https://avatars.discourse-cdn.com/v4/letter/m/57b2e6/32.png) [@MissBungle](https://boards.straightdope.com/u/MissBungle)\ **Post date:** [March 12, 2003, 9:24am UTC](https://boards.straightdope.com/t/feeling-tired-after-eating-fast-food/160669/3 "2003-03-12T09:24:55Z")
> [@](#): > > \*Originally posted by mipiace \* > \*\*Does your body accumulate a “tolerance” to high fat foods? \*\* My guess would be that YOU have more of a tolerance to the tired feeling, when eating mostly fast food. But I don’t know. Obviously fast food (typical burgers and such) have low amounts of fiber and nutrients. It’s not surprising you don’t feel as well after eating them. Lots of sodium in those foods too. Possibly you feel sluggish because you are thirsty. ---
**Author:** ![MissBungle](https://avatars.discourse-cdn.com/v4/letter/m/57b2e6/32.png) [@MissBungle](https://boards.straightdope.com/u/MissBungle)\ **Post date:** [March 12, 2003, 9:27am UTC](https://boards.straightdope.com/t/feeling-tired-after-eating-fast-food/160669/4 "2003-03-12T09:27:00Z")
> [@](#): > > \*Originally posted by MissBungle \* > \*\*My guess would be that YOU have more of a tolerance to the tired feeling, when eating mostly fast food. > > \*\* sorry, I didn’t explain myself the way I wanted to. I mean, if you are on a steady diet of fast food, perhaps you just get used to feeling THAT WAY, in which you have described. Maybe you forget how much better your body can feel. ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [March 12, 2003, 9:27am UTC](https://boards.straightdope.com/t/feeling-tired-after-eating-fast-food/160669/5 "2003-03-12T09:27:40Z")
One theory is that it’s an insulin spike: you eat a substantial amount of (“too many”) carbohydrates, and your insulin levels ramp up to process them. About an hour later, in the absence of more carbs, there is excess insulin flooding your bloodstream, leading to sleepiness. When I gave up carbs, this problem went away for me. ---
**Author:** ![mipiace](https://avatars.discourse-cdn.com/v4/letter/m/eb9ed0/32.png) [@mipiace](https://boards.straightdope.com/u/mipiace)\ **Post date:** [March 12, 2003, 2:25pm UTC](https://boards.straightdope.com/t/feeling-tired-after-eating-fast-food/160669/6 "2003-03-12T14:25:27Z")
It feels like an insulin spike. (Yuk) I typically eat a lot of vegetables, fruits and low fat protein so whenever I eat high fat, I feel like I have been sedated. No wonder my Mom used to tell me that kind of food was poision!