As we saw in Chapter 2, during focused training for a marathon or half marathon it is not necessary to count calories, nor is it advisable to consciously eat less for the sake of losing weight. At that time fitness-building is your top priority, which requires that you eat according to your appetite to ensure that your body is supplied with plenty of food energy. Maintaining very high diet quality will suffice to rid your body of excess fat even as you continue to eat as much as you’re hungry for.
The situation changes in a quick start. Your top priority during this period is losing weight quickly and to do this you must consciously reduce the amount of food you eat in order to create the calorie deficit without which weight loss is impossible. In principle, the larger your calorie deficit is, the faster you will drop the pounds. But for runners a modest calorie deficit is better than a large one, even in a quick start. While building fitness may not be your top priority at this time, you’re still working out and trying to lay a foundation for the race-focused training to come. Eating too little would sabotage these efforts. Also, if your calorie deficit is too large you will lose more muscle and less fat than you would with a moderate calorie deficit.
In the 1980s researchers at Rockefeller University looked at the effect of daily calorie deficits of different sizes on weight loss. As they expected, the fewer calories the subjects consumed, the more weight they lost. What wasn’t expected was where the weight loss came from. In individuals who reduced their daily calorie intake by a moderate amount, 91 percent of the weight lost was fat and a mere 9 percent was lean body mass. But in subjects who severely reduced their calorie intake, fat represented 48 percent of the total weight loss and muscle 52 percent. So it appears that larger calorie deficits result in large amounts of muscle loss. For runners, loss of muscle is likely to reduce strength, power, and overall performance.
I suggest a moderate daily calorie deficit of 300 to 500 calories during a quick start. If you’re within 10 pounds of your racing weight, 300 calories is sufficient. If you’re more than 10 but fewer than 20 pounds above your racing weight, maintain a deficit of 400 calories per day throughout your quick start. If you’re more than 20 pounds over your optimal racing weight, aim to consume 500 fewer calories than your body uses each day. Deficits in this range will enable you to lose weight fairly quickly while preserving muscle mass, especially when they are combined with the other quick-start methods.
To determine how many calories you will eat daily in a quick start it is necessary to subtract your chosen deficit from the average number of calories your body will burn daily in the quick start. There are various online tools you can use to create an estimate of the number of calories your body uses daily. Some are better than others. The best ones for athletes allow the user to input detailed information about exercise. One such calculator can be found at nutritiondata.self.com. When you use this tool, enter the average duration and intensity of exercise you intend to do in your quick start. Even though you will train harder than this on some days and not as hard on others (hence you will burn more calories on some days and fewer on others), these fluctuations will balance out over the course of a full week of training, making your calorie burn estimate and your daily calorie deficit accurate.
| DAILY CALORIE DEFICIT BY WEIGHT CHART: | |
| WEIGHT GOAL | CALORIE DEFICIT |
| Within 10 pounds | 300 calories |
| Between 10 and 20 | 400 calories |
| More than 20 | 500 calories |