[Cloud9Fitness]

There are no conclusive answers to your specific question, but these points may help your clients make the best decisions.

Protein supplementation has been repeatedly shown to improve muscle anabolism after a workout with a variety of techniques. Some techniques include 20 grams of whey protein alone, milk (8 grams of protein and 12 grams of carbohydrates), and 1-to-1 protein/carbohydrate solutions (0.15grams/kg). As you can see they have a variety of different protein/carb proportions.

Protein supplementation's effect on glycogen stores has not been directly evaluated. Some amino acids are glycogenic, but after a workout they are theoretically going to assist in providing energy during the post-workout return to resting VO2, and not restoring glycogen. (Atleast theoretically not as quickly as either high or low glycemic carbohydrate)

Carbohydrate ingestion at loading doses is shown to be important for glycogen restoration in athletes. Higher doses may not be needed for average gym-goers as their glycogen storage limit is lower.

All this science is well and good, but what is the big picture?

I suspect the best approach for an average gym-goer trying to lose weight is to calculate the the amount/composition the individual needs during the day. Split those requirements into meals and snacks. Then suggest one of the snacks as a post-workout snack that fits into this ultimate plan. I do not see why it should not simply match their diet plan (healthy goals may include 50-60% carb/20-30% protein/20-30% fat with reduced caloric balance). Some options off the top that mimic this approach are 2 cups of skim milk post workout, muscle milk, or peanut butter on apple slices.

Simple diet planning guides can be found online. One option includes Cloud9Fitness' Metabolism and Fitness Nutrition course. It includes computer applications that make these calculations easy to perform with a client during a consultation.