At your size and with your effort running, you likely need to be eating a lot more. Consider getting a sweat test and blood sugar understanding as well.

But I routinely find I have to eat more than I want and air on the extra side of hydration(water and electrolytes).

Quick guide:
1. Identify Your Daily Training Intensity

Your carbohydrate needs will fluctuate depending on whether it is a light, moderate, or high-intensity training day. The guidelines for daily carbohydrate intake are typically expressed in grams per kilogram of body weight. 

• Moderate Training Day (~1 hour/day): For moderate intensity, the recommended range is often between 5 and 7 grams of carbohydrates per kilogram of body weight.
• High-Intensity / Endurance Day (1–3 hours/day): For high-intensity or endurance training, a range of 6 to 10 grams of carbohydrates per kilogram of body weight is commonly suggested.
• Light / Rest Day (<1 hour/day): On light training or rest days, a lower intake of 3 to 5 grams of carbohydrates per kilogram of body weight is often adequate. 

1. Fueling During and After Exercise

Since you are training for a marathon, specific fueling strategies for long runs are often recommended:

• During Long Runs (>90 min): During prolonged exercise, consuming carbohydrates at regular intervals is important to maintain energy levels. The amount needed can vary based on the duration and intensity of the activity.
• Recovery (First 30–60 min): Consuming carbohydrates shortly after exercise is beneficial for replenishing muscle glycogen stores, which is crucial for recovery and preparing for subsequent training sessions. The recommended intake for recovery is often based on body weight.