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Fructose is the problematic sugar our bodies turn to fat the most readily, and if you are programmed to be fat, an apple will make you that much fatter.

If your caloric intake is not exceeding your caloric expenditures, an apple will have no effect on your fat. Besides, there is very little de novo lipogenesis in the human body. We're not like pigs and cattle. Fat gain is due almost entirely to dietary fats. Here is the order of storage capacity of the three macronutrients: fats > glucose > proteins. They range from comparatively unlimited storage for fats to no storage form for proteins. If your dietary intake exceeds your kilocalorie expenditure, the excess is stored. Since there is only about 3 days of storage for glucose in the form of glycogen, the so-called animal starch, and since there is no storage for proteins, the burn order for macronutrients is protein > glucose > fats. That is, proteins are preferentially metabolized over glucose (including all the other dietary sugars that are eventually converted to glucose unless, like fructose, they are used in DNA synthesis or they're metabolized in the glucose pathway). Glucose is preferentially metabolized over fats. When someone's energy intake consistently exceeds his energy output, the substrate oxidation shifts away from fats (the primary energy source your body runs on--even muscles, especially the heart) and toward carbohydrates. This is simply a matter of protection against too high a level of serum glucose. If your proteins get glycosylated, you get screwed up faster and worse than if you just put on weight. If you really pack in a huge amount of excess calories with a high percentage of carbohydrates, you may produce some fat via de novo lipogenesis, but it'll be a tiny fraction compared to stored dietary fat.

With respect to acid reflux, eat only very lightly in the evening. Going to bed with a mostly empty stomach will have a greater positive impact on acid reflux than almost anything else.

And, yes, I am an expert (Ph.D. Human Nutrition/Nutritional Biology, University of Chicago).

"...the burn order for macronutrients is protein > glucose > fats."

I'm a little confused about this statement. Doesn't the burn order depend on the ratio of the nutrients in the your blood serum at a given time? I also thought it was glucose, protein, then fat. If no glucose, then your body starts to cannibalize it's muscles for protein, while converting fat also.

And where does the glycemic valuation of a given carb fit into your burn order - if at all? Weight lifters are told to eat more carbs then protein after workouts because of glycogen depletion and that certain carbs will restore the ATP quicker than protein. Of course, they need additional protein to repair the muscle fiber breakdown. Maybe I'm mixing up the terms or relying on old info.

Besides, there is very little de novo lipogenesis in the human body.

This paper argues otherwise. Do you have any more up to date references than this?

Fructose, insulin resistance, and metabolic dyslipidemia

A high flux of fructose to the liver, the main organ capable of metabolizing this simple carbohydrate, perturbs glucose metabolism and glucose uptake pathways, and leads to a significantly enhanced rate of de novo lipogenesis and triglyceride (TG) synthesis, driven by the high flux of glycerol and acyl portions of TG molecules from fructose catabolism.