Conventional wisdom has it that you should eat a nutrient-packed snack about 90 minutes before a run in order to maximize your training potential. Busy moms, however, rarely have 90 minutes plus run time to themselves and sometimes have to get up and out the door before the rest of the house wakes up and demands attention. Running without food can affect your performance, but you're not really putting your long-term health at risk by skipping breakfast before your run. Running without water is dangerous and should be avoided.
Less Fuel In The Tank
A 1987 study published in the "Journal of Applied Physiology" found that experienced marathon runners reached exhaustion 45 percent sooner when they were tested after a 27-hour fast versus three hours after a meal. A more recent 2010 study published in the "British Journal of Sports Medicine" found that fasted runners did not cover the same distance during 30-minute time trials than runners who had eaten. The moral of the story is that mom was right all along. Breakfast is the most important meal of the day, and while you can run without it, you'll probably find it difficult to go as far or as fast.
New Challenges Take You To New Levels
If you run without food, you are teaching your body to push hard in a depleted state. If you're running for longer than 30 minutes, your body will tap into fat stores for energy more quickly than if you run after eating, so over time you'll start to shed fat accumulation. If you are training for a race, you can train food free to challenge your body to use those energy stores, but you'll want to eat something before your speed workouts, because you can train faster with fuel. Fueling on race day after training on an empty stomach will give you a performance boost.
Sip, Don't Skip
Dehydration is dangerous but preventable. If you're setting out for a short 20- or 30-minute easy jog before getting the kids on the bus, then you're probably OK with no water, as long as you replenish fluids immediately after your run. Anything longer, though, and you start playing a risky game that just has no payoff. You wont make any gains by running dehydrated, and in fact it can impact your performance and overall health. Meals before running may be optional, but not drinking water really isn't.
You may find that the jostling action of running upsets your stomach if you've eaten anything beforehand. If you get crazy hungry while you're running, try something small, such as a slice of toast with peanut butter, an hour before heading out. If your tummy is still sensitive, try skipping the food until you get back. Every mom's body is different; some can tolerate running on an empty stomach, and some can't. There's no right or wrong way to do it. The important thing is that you're getting out there and moving, setting a strong, healthy example, and being the best mom -- and runner -- you can be.