Dorian Yates was a huge advocate of eating carbohydrates leading into a contest, whereas a bodybuilder like Ben Pakulski is extremely carb-sensitive. New research suggests that it may be your genes that determine how your body handles carb metabolism. One study looked at a gene called AMY1 to measure starch digestion between differing groups of people. AMY1 is a salivary enzyme that begins the breakdown of starch in the mouth. AMY1 variation exists between different members of the human species. Humans can contain anywhere between two and 15 copies of the AMY1 gene. The more AMY1 gene copies a person has, the better he is at digesting carbohydrates.
The theory suggested by researchers is that the AMY1 gene provided an evolutionary advantage for some people who had to rely on high-carbohydrate diets where meat was lacking. This led to diversity in one specific gene responsible for the breakdown of carbohydrates, alpha-amylase (AMY1). This may be a major reason there is so much variation from person to person when it comes to carbohydrate intake. Researchers examined differences in AMY1 copies among individuals and how it affected blood glucose levels after carbohydrate rich meals. The experimental group was made up of healthy, non-obese individuals, and they were divided into a high-amylase group and a low-amylase group. They came into the lab twice, once to ingest starch (experiment) and glucose (control). The low-amylase group had higher blood glucose levels than the high-amylase group during starch consumption. This increase in blood glucose levels lasted for the two hours that the participants remained at the lab! Interestingly, when the low-amylase group consumed the glucose, blood sugar levels remained relatively consistent with the high-amylase group and the blood sugar did not stay elevated as long as when they ingested the starch.
This is an extremely new phenomenon when looking at the individuality of carbohydrate digestion. All we know about this topic is that some people respond to the same meal of starch differently. This may also explain why some people such as Yates can handle high carbohydrates leading into a contest whereas other can’t. - FLEX