Do you have all of your barracks and naval bases turn on 'enabled' ? If so shut them off and see if this helps. Also if your army is huge with units that have infantry\men attached they also have a daily food cost, send them into war and thin it out a little. Food\Manpower\Army Size\Population is a balance in the game, if out of balance well you can see what happens.

Also don't build up on provinces that don't produce anything unless you need to. As you build your population increases and the need for resources increases with it.

thanks for the info. although my food shortage is not as bad as razorwire's, my food production is now almost out of the red

One of the dangers of gold-spamming up a bunch of units is that you may not be able to support them with your food production, and buying food with gold can become a very expensive proposition very quickly if you have built an unsustainably large army. You should always be aware of your food production when adding units, because acute food shortages can have a dramatically negative impact on the morale of your provinces, which in turn can negatively impact resource production including food. I have seen several catastrophic instances of food shortage morale death spirals caused by acute food shortages, followed by declining morale and production, widespread rebellion of provinces and the destruction or defection of units. Building an army that is too large for your food production is a big mistake.

You should also be conscious of the fact that different types of units consume greater or lesser quantities of food. Infantry, for example, are relatively cheap and quick to produce, but they are the chow hounds of your army. You may want to spend some time familiarizing yourself with the various unit spec sheets that you can access via the research menu.

That should not happen. Your resource production should increase incrementally as new infrastructure or industrial complexes are completed, but there is one comprehensive update of production and consumption at midnight German time (Bytro Labs is located in Hamburg). Also, if you think that your production should be higher based on recently completed buildings, hit the refresh button on your browser. Sometimes that will cause your production numbers to refresh.

Food tip no. 1. Always try to maintain your food production in the black (er, green, in the case of your resource production menu), even if it is only a small hourly surplus. Build your food production as you produce new units to maintain production/consumption balance. If you have no room to increase food production, stop producing more units except as replacements.

Food tip no. 2. Always maintain a reserve of 10,000 to 20,000 tons of food. It is almost unavoidable that you will go into food production deficit when you conquer a large amount of territory in a small amount of time. Until morale increases in your newly conquered food provinces, you may not even be covering 100% of the food consumption of your new provinces. Balance is KEY.