In the bodybuilding scene, the logic that you need to consume carbohydrates to build muscles is this:
Protein calories will be used as an energy source when the body is
lacking fat or carbohydrate calories for fuel. When the body receives
sufficient quantities of proteins, fats and carbohydrates, protein
will carry out its specific functions.
Note, that the article never says you need to consume "a lot" of carbohydrates or have them with every meal; they don't even need to be carbohydrates - fats will do the same: provide calories for energy, so the proteins won't get burned and could be incorporated into the muscles.
Garri, which is made from cassava, contains a lot of soluble fiber, which can cause a lot of gas if consumed in great amounts. There are other high-carb foods with much less soluble fiber, for example, bread, pasta, potatoes and rice.
Having >60% carbs in your diet is a risk factor for increased blood triglycerides, which might be further associated with increased risk of diabetes or heart disease, though (PubMed, 2000).
According to the following study, carbohydrate intake as such does not help to increase muscle mass: Is carbohydrate needed to further stimulate muscle protein synthesis/hypertrophy following resistance exercise? (PubMed, 2013)
In conclusion, whilst it cannot be excluded that carbohydrate addition
may provide benefits for recovering athletes, on the basis of
available data, no further beneficial actions of carbohydrates,
irrespective of GI, are evident concerning muscle hypertrophy when a
protein supplement that maximally stimulate muscle protein synthesis
Another study (PubMed, 2004):
We conclude that ingestion of carbohydrates improved net leg protein
balance after resistance exercise. However, the effect was minor and
delayed compared with the previously reported effect of ingestion of