Junk Food Law :
"Junk food is delicious, but only upto around 2 portions.*"
(* "portion" varies from junk food to junk food.)
I'm not a huge junk food junky... but I do like pizza, fries, chips, samosas, cookies, chocolates, puffs, muffins etc...
After extensive research and experimentation, I've noticed a pattern...
The first bite is always the best... and the second is pretty darn good too! In fact the entire first piece is yum! Tastes good, feels good... makes you wanna go for another portion. You bite into the second one - hmm... still good... but by the time you finish the second portion, the "yummyness per bite" has started to go down...
You might go for another (3rd) portion and then suddenly you'll notice this small component of "yuckiness" with each bite... (usually the side effect of oil, refined starch etc...) Now as you keep going, "yumminess per bite" keeps dipping slowly, while "yuckiness per bite" goes way up.
Any more junk and you are so going to regret it within the next hour - depending on the particular choice of junk, its going to be acidity, nausea, sugar rush or feeling like you've got a brick in your stomach.
My research shows that everyone in general responds to Junk Food this way... Some people are more tolerant of Junk (their Junk Food Threshold is higher), but in general, this pattern seems to be pretty universal.
After tons of experimenting, I'm proud to present...
Pratik's recommended junk food amounts :
Pizza - 2 slices.
Subway Cookies - 3/4th for single chocolate, and 1/2 for double chocolate.
Blueberry Muffins - 1.25 (this one's tricky)
French Fries - about 5- 10 fries max.
Cake - 2 pieces max!
Samosas - 1 (I can't do more without feeling queasy, unless I'm starving and it's fresh + hot)
Potato Chips - about 5 - 10 chips max.
Kurkure - about 5 - 8 crisps.
Chaat - exactly one plate. No more, or you'll regret it!
Paani Pooris - about 5.
Heat Caveat : 
When the junk is fresh/hot, the apparent "yum" factor goes up, and the apparent "yuck" factor shrinks. Hence it's very easy to cross the Junk Food Threshold at such times... You might regret it after an hour, but very often, it is totally worth it! ; )
Pratik's Junk Food Principle :
- Thou shalt under no circumstances eat junk food past the Junk Food Threshold.
- For optimal enjoyment of yum vs yuck, stop 25% short of the Junk Food threshold.
- The only exception is when both you're starving & the junk food is rare + fresh + hot + super yum.
- Always get your junk fresh and hot for maximum Yum!
All right, time to junk out now! : )
 I know they don't rhyme... But I'm sure at least a couple of people will think they do... ; )