Significantly heavier or lighter individuals will need proportionally more or less carbohydrate.
Simply use the value of 8-10 grams of carbohydrate per kilogram of LBM as a guide.
In the second 24 hours, glycogen resynthesis rates decrease (1) and a carbohydrate intake
of 5 grams/kg is recommended to further refill muscle glycogen stores while minimizing the
chance of fat gain. For many individuals, the small amount of additional glycogen resynthesis
which occurs during the second 24 hours of carbohydrate loading is not worth the risk of regaining
some of the bodyfat which was lost during the preceding week.
Type of carbohydrates
The type of carbohydrate consumed during a carb-up can affect the rate at which glycogen
is resynthesized. During the first 24 hours, when enzyme activity is at its highest, it appears that
the consumption of high glycemic index (GI) foods promotes higher levels of glycogen resynthesis
than lower GI carbs (5,7,8).
Glycogen resynthesis during the second 24 hours has not been studied as extensively. It
appears that the consumption of lower GI carbs (starches, vegetables) promotes higher overall
levels of glycogen resynthesis while avoiding fat gain by keeping insulin levels more stable (9).
Most individuals find that their regain of bodyfat, as well as retention of water under the skin, is
considerably less if they switch to lower GI carbohydrates during the second 24 hours of
carbohydrate loading.
Fructose (fruit sugar, which preferentially refills liver glycogen) will not cause the same
amount of glycogen resynthesis seen with glucose or sucrose (5,8). Whether liquids or solid
carbohydrates are consumed also appears to have less impact on glycogen resynthesis as long as
adequate amounts are consumed (10).
Anecdotally, many individuals have had success consuming liquid carbohydrates such as
commercially available glucose polymers during their first few meals and then moving towards
slightly more complex carbohydrates such as starches.
Timing of carbohydrates
While it would seem logical that consuming dietary carbohydrates in small amounts over
the length of the carb-up would be ideal, at least one study suggests that glycogen resynthesis
over 24 hours is related to the quantity of carbs consumed rather than how they are spaced out.
In this study, subjects were glycogen depleted and then fed 525 grams of carbohydrate in either
two or seven meals. Total glycogen resynthesis was the same in both groups (11). A similar
study compared glycogen resynthesis with four large meals versus twelve smaller meals (12).
Glycogen levels were the same in both groups.
Both of these studies suggest that the quantity of carbohydrates is more important than
the timing of those carbohydrates. From a purely practical standpoint, smaller meals will
generally make it easier to consume the necessary carbohydrate quantities and will keep blood
sugar more stable.
Depending on when the carb-up is begun, some dieters may have to go long periods of time