Will eating after 8 p.m. cause my food to be stored as fat?

No, it will not. People have different schedules and some have to eat later in the day; those people will not automatically become overweight. Weight and fat gain are dependent upon you eating more calories than you burn, not the time of day those calories are eaten.This myth started due to the fact that most people eat a lot of calories and make poor food choices later in the evening. These late night junk food binges provided calories above maintenance and therefore contributed to fat and weight gain. Rather than changing your eating patterns, make wiser food choices, eat smaller portions, and/or save some calories for later in the evening if that is when you like to eat. To date, there has not been an enzyme identified that causes fat storage after a certain hour of the day.

Absolutely not.  I have notice that some of these so called diets out there are trying to tell you not to eat after a certain time so you will lose weight.  Bottom line is if you burn more calories than you take in you will lose weight.  Some people have different schedules to eating based on lifestyle.  It does not matter when you eat just as long as you burn more than you eat. 

The answers above are great and truthful.  The biggest factor in gaining or losing fat is total calories in versus burned and it is not just in a day but a cumulative effect over a long period of time.  A bad or good day does not make or break a lifestyle.

The majority of my clients follow a plan at least 50% carbohydrates but some of my more serious clients who are either athletic or competitive bodybuilders will follow something a bit different.

Many of my bodybuilders for instance follow a lower carb diet with carb refeeds at certain times in the week.  These refeeds are usually in the evening around 10 or 11 and usually 600 to 1200 calories and 100 to 300 grams of carbs and these individuals get leaner.  In fact on these type of plans my clients will generally lose fat slower if they do not consume these meals.

I have other clients who do rotational diets or plans that utilize higher calories one day and lower calories the next.  The higher days are feedings throughout the day and higher calories later at night and they are losing at least a lb of fat per week.

My point in this is the timing of your meals is not nearly as important as the nutrition as a whole.  Cumulatively if you are in a caloric deficit throughout the week you will lose fat.  I use the examples above to show you that I have clients get in phenomenal shape and some of them eat high carbs late into the night. 

As long as you are within your caloric boundaries for the day, not at all!  As Jeff mentions above, one of the main reasons so many people apply a cut off (or "close the kitchen") time to their eating is to avoid overeating late at night, when we are most apt to eat due to boredom, stress or habit.  

That’s one of those myths that has been around for quite some time. In reality, eating at night does not necessarily contribute to weight gain or cause you to store more fat. You only end up gaining weight if your total calories eaten throughout the entire day exceed the calories you burn. For some people eating at night can be a problem when they severely restrict calories during the day and then get so hungry at night that they binge on excess calories. As long as you track your calories throughout the day and don’t exceed the recommended limits, you can eat late into the night without putting on weight.

The answers submitted to this question by the Elite Trainers might be true for trained athletes, but for the average person trying to avoid gaining weight, not eating after 8 p.m. appears to be worthwhile.

People who eat a relatively large proportion of their daily calories in the morning tend to consume fewer total calories per day, whereas people who consume a relatively large proportion of their daily calories late in the evening tend to consume more total calories per day (J Nutr 2004;134:104-111). In addition, the timing of calorie consumption affects body weight independently of its influence on caloric intake. When research subjects ate their entire daily food allotment (2,000 calories) in the morning, they lost weight. However, when they consumed the same number of calories entirely in the evening, they gained weight (Experientia 1976;1976;32:1081-1084). These findings support the recommendation of the pioneering nutritionist Adelle Davis that we should "eat breakfast like a king, lunch like a prince, and dinner like a pauper."

Further information about preventing and treating obesity is presented in chapter 333 of my textbook, Nutritional Medicine (www.doctorgaby.com).