First, congratulations on achieving your goal of running the marathon. Now that you're most likely running fewer hours per week than you were during the height of your training, it's important to adjust your caloric intake accordingly. So far, your weight gain is completely normal. Many athletes gain a handful of pounds following a big event, and typically it's actually good for your immune system. Maintaining a very lean physique can compromise your ability to ward off infection, so gaining a few pounds over the past few weeks may help you stay healthier through the fall.
What you're afraid of is that your four pounds is going to balloon to 15 pounds, right? Well, that can happen if you continue to eat like you're in full-tilt training mode when you're not. This happens to a lot of summer-sports enthusiasts when the seasons change; it's very easy to cut back on exercise at the end of a long training season, but harder to cut back on food intake. Try the following tips to gradually reduce your caloric intake over the next week, and your weight is likely to stabilize quickly.
1. Fill Up on Fiber: Add more fruit and vegetables to your daily meals and snacks. These foods contain a lot of water and bulky fiber which make you feel full quickly, even though they don't deliver many calories. Good choices include citrus fruit (oranges, grapefruit, clementines, etc.), greens (kale, Swiss chard, cabbage, endive, Romaine lettuce), and beans (black, pinto, kidney, garbanzo, etc.).
2. Cut Back on Grains: As counterintuitive as this sounds, you don't need as much carbohydrate energy from whole wheat breads, pasta, and brown rice right now. It's not that these foods are bad for you; they're actually great for your health and performance, but you don't need to rely on these foods for extreme amounts of energy during this portion of the year. Your total carbohydrate intake (including fruit, vegetables, and grains) was most likely very high, up to 70 percent of your total calories, during the height of your training. Now that you're training fewer hours, this percentage can come all the way down to about 60 percent of total calories. Cutting back on grains is a good way to achieve this reduction, especially when you're trying to consume a lot of fruit and vegetables for their fiber.
3. Watch Out for Unnecessary Calories: When you're training hard, a 16-ounce white chocolate mocha (nonfat milk) can be a nice treat, but when you're weekly energy expenditure falls because you're not training, that's 440 calories you don't really need. For comparison, a 16-ounce cup of coffee or Americano contains fewer than 20 calories. Similarly, there are countless sources of wasteful calories all around us: the cookies a coworker brings in to the office, a can of soda instead of water (140 calories), airplane peanuts you don't even like it all adds up.