1. Coffee sweet is able to treat gastric pains that are caused by prolonged lack of food. (given)
2. Thus, coffee sweet contains milk that can neutralise the acid chyme in the stomach.
3. There is high milk content because milk must be present in sufficiently high amounts for it to take effect.
4. Since the amount of coffee present in the coffee sweet is approx. proportional to the amount of milk present, there is high coffee content too.
5. A high coffee content implies that the level of caffeine is also high.
6. A high caffeine level causes a person to feel awake.

Disclaimer
The original coffee sweet theorem was criticised for the lack of linkage between the idea that a high milk content implies a high caffeine level. This was initially explained wrongly by Gim Thia, who simply gave a generalisation that since there is high milk content, there is "high everything". After some thought, Gim Thia found the missing link and presented the new thesis the next day.
Hence, William has got a wrong perception of the coffee sweet theorem (even the original one).

Sorry everyone, just wanted to play along with William and establish the facts. No offence to William whatsoever. =)