During the Transition period after your last race season you probably gained some weight. That is expected. And it’s probably a good thing - depending on how much weight you gained. Trying to stay at your optimal race weight year round is not good for your health. It’s also not good for your psyche. Staying focused on maintaining race weight 12 months of the year, regardless of your training load, requires a monk-like lifestyle of continual sacrifice and near suffering.
So I hope you’ve enjoyed life a bit and gained some weight in the last few weeks. The Base period is the time to start trimming down any excess beyond your best training weight. Training weight is a bit heavier than race weight. Your training weight by the end of the Base period may be roughly three to five percent more than your race weight – the weight you will have on the day of your first A-priority race. The higher workload of the Build period should be enough to gradually bring your training weight down to your racing weight by race day.
The extra calories you are burning as you move into the Base period may be enough to help you accomplish this initial weight loss. If not then you need to become more aware of your eating habits and modify them appropriately. Keeping a food log is a proven way of doing this.
Athletes who have been through this weight-loss process before generally know what they need to do to shed the extra flab. What I have found works best with the athletes I’ve coached is to greatly reduce their intake of starch and sugar replacing these foods with non-starchy fruits and vegetables. Examples of starchy foods are pastries, cereal, bagels, bread, corn, rice and potatoes. Limit your intake of such foods to the first 30 minutes following your long aerobic endurance and higher-intensity muscular endurance workouts. This will compromise your recovery a bit, but it’s better to do that now than in the last few weeks before your A race when recovery is becoming increasingly important to race performance.