HFCS is the devil, the cause of the obesity epidemic?
Not so fast according to Guyanet Stephen.
Fructose is good if you are not overeating but turns ugly when you do overeat. FYI half of sugar is fructose, the other half is glucose.
It signals the liver to store glucose. The good is this reduces insulin from glucose and also lowers blood sugar levels. The bad is if your liver is already full up with glycogen, fat gets shuttled straight to your fat cells (especially visceral fat). The other bad is that for sugary drinks, where the speed of calorie absorption in your intestinal tract is a concern, the fructose + glucose increase the calorie uptake rate as they use different transporters. That will tax your pancreas and liver no doubt.
Other possible conditional effects:
replacing some glucose with fructose pre endurance workout reduces the ravenous hunger which some people experience afterwards. Also, it may reduces metabolic slowdown and protein wasting from dieting. (This would abolish the immune system rejuvenation of a 3day+ fast.)
Application: slow down fructose absorption by (1)eating it in a fiber matrix (fruit), (2)at the end of a meal, or (3)with cinnamon which slows conversion of sugar into absorbable glucose and fructose.
Dinner is the time when topping of liver stores makes the most sense, as your body will be using that until you break the nightly fast 12-14 hours later.
If you get ravenous after running or other calorie intense exercise, replace half the carbs in your pre-workout meal with sugar and see if that helps. On race day galactose is probably better than fructose. Strength training does not burn enough calories for this to be an issue.
Fruit may also be ideal to break longer fasts with to ensure a clean rapid transition out of fasting mode. Remember in nature, good moderation is cycles, not being stuck in the middle.
From an appetite/overeating perspective I gather sweet by itself does not cause overeating from by over stimulating appetite. Sweet+fat together is what blows our mind. Also, the low nutrient per calorie density of sugar is a cause for concern. Spices may help.