That's right, eating too little at the wrong times can actually have a negative effect on your weight loss efforts. Don't get me wrong, at the end of the day weight loss is still a very basic calorie calculation: weight lost = calories out - calories in. Consume more than you burn and you gain weight. Burn more than you consume and you loose weight. Simple math.
However, eating too little at critical times of the day, like breakfast or prior to exercise can actually have a negative effect on your ability to loose fat.
Skipping breakfast, for instance can create a hormone imbalance that triggers the body to go into "starvation mode," and consequently triggers the body to store more fat than it otherwise would by reducing your metabolism. Not good.
Further, as the day progresses, this hormonal imbalance unnaturally increases appetite to the point where you're far more likely to overeat for your next couple of meals. That's even worse.
Eating too little prior to exercise is another frequently made mistake.
Whether you're heading to the club to loose body fat, add muscle tone, or just feel good about yourself, it is critical that you have a small pre-workout meal.
And here's why.
Energy for exercise always comes from a blend of protein, carbohydrate, and fat. But fat sources only work at very low intensity levels, and carbohydrates are quickly utilized and must be constantly replenished.
So, while you might hope that your body will always use fat as an energy source during exercise, stored fat is metabolized ONLY when you are either sedentary or exercising at a very, very low level of intensity. You will, indeed, burn more calories when you exercise at more rigorous levels, but you'll burn no more fat. Check out my Heart Rate Zone Training to Look and Feel Fantastic report for LOTS more detail on this.
Most exercise is aerobic in nature. The energy source that will help you work harder to burn more calories, and work more efficiently to recruit additional muscle fibers is carbohydrates. Unlike fat, which is stored as fat, carbohydrates are stored in the blood stream, muscle tissues, and organs as glycogen and glucose (and, technically ATP at the cellular level, but we'll ignore that for now).
These immediately available "sugars" are your primary energy source for exercise ... at least until they're gone, which can be in as little as 20 minutes, depending on your metabolism and the nature of your exercise. Once the supply is spent (metabolized to exercise), your body needs to replace those spent sources with new sources .. .your pre-workout meal.
So, when you're consuming your pre workout meal, you're really filling your gas tank for the second half of your workout.
If you get it right, you're in good shape for high energy levels and higher levels of intensity during the second half of your workout. If you get it wrong, you'll "hit a wall", struggle with even moderate intensities, and ask your body to metabolize less efficient sources for energy, like proteins. That's right, even if you've got 30 pounds of body fat to loose, if your body needs energy sources beyond the immediately available carbohydrate sources, it doesn't convert your stored fat, it converts proteins!
And it gets worse yet, for if those proteins aren't in your bloodstream (from a consumed meal), your body converts stored proteins ...your muscle tissue ... through a process called catabolism.
And if you are catabolising you will almost certainly gain fat because maintaining lean body mass is a key factor in loosing body fat!
So, (ahem), here's the skinny on your pre-workout meal. You don't need to have much, but be sure that you have a few hundred (200 to 400, depending on your body weight) balanced calories between 30 and 60 minutes prior to exercise. This window will vary from person to person (and your hydration levels and prior daily food intake), but 30 to 60 minutes ahead of your workout is a good place to start. A well balanced snack should consist of approximately 25% protein, 65% carbohydrate and 10% fat. One half of a peanut butter sandwich and half a banana handle this perfectly. Or a yogurt and a few crackers.
This pre-workout requirement is also well recognized, and aggressively marketed by the nutritional supplements industry (Cliff, Powerbar, Gatoraide, etc.). Products from these suppliers also nicely handles the requirement. However, just be sure that you consume the product far enough ahead of exercise for benefit: it takes most digestive systems 30 to 40 minutes to move food to the bloodstream. Consuming these products during exercise is almost always too late for any benefit for exercise shorter than 90 minutes.