So you've decided to start exercising - and like most of us, the goal is to get into shape and lose weight. Unfortunately, many of us place more emphasis on the number on the bathroom scale as opposed to body composition or the percentage of muscle to fat.
As a result, after many months of dieting and exercising, what we see in the mirror isn’t exactly what we envisioned. There’s no tone or definition – arms, legs and stomach are still flabby. How can this be? What many of us don’t know is that our exercise and diet regime has resulted in a loss of muscle mass as well as actual weight.
No one wants to have smaller muscles from exercising. The goal is to improve body composition: muscles burn more energy than body fat at rest, so if you develop more muscle and have a higher muscle-to-fat ratio, you’ll burn extra energy as a result – which means burning more calories. So how can one lose fat without losing muscle? This can be tedious. Figuring out how many carbohydrates, proteins, and fats to eat, and when, can also be very confusing. However, there are some guidelines surrounding exercise and diet that can help you reach your ideal weight while protecting your muscles.
Understanding how our muscles use what we eat is the first step in knowing what to do and what not do. When we use our muscles, a chemical reaction takes place that breaks down something called ATP (Adenosine Triphosphate) to make energy. ATP is generated from three energy systems in the body:
ATP and Creatine Phosphate System – Used for explosive power such as sprints and high-power needs such as running a 100-yard dash. Creatine Phosphate is used in this system and is formed from creatine. Creatine is a naturally occurring amino acid (proteins building blocks) found in meat and fish. It’s also made by the body in the liver, kidneys, and pancreas and stored in muscles, where it’s used to produce ATP.
The Glycolysis System – This system breaks down glucose and is used for medium endurance exercise such as running a ½ mile. When carbohydrates are eaten, the digestive system breaks them down to supply the body with glucose for immediate use to produce ATP. If there is a surplus of glucose, the body stores it in the liver as glycogen for later use. Glycogen can also be used to form ATP, and in the liver it can be converted back into glucose when needed. Intense exercise can deplete the muscles and liver of glycogen, as can a diet low in carbohydrates.
The Oxidative System – Used when more endurance is needed, such as the energy required for a 10-mile run or a marathon. Protein and fat is used by this system. Protein, particularly useful during this type of prolonged activity, must first be broken down into constitute parts (amino acids) before being converted into glucose to produce ATP. Fat, stored as adipose tissue, is also used in this system. However, it’s less accessible as it must also be broken down (oxidized) first. So although fat is a vast stockpile of fuel, providing more energy than other sources, its release is too slow for very intense activity.
The intensity and duration of exercise determines what energy system the body uses to generate energy. Typically, after about 20 seconds of intense exercise, ATP reserves are depleted and the muscles must then look to other sources of fuel. Glycogen, the stored form of glucose, is used first to replenish ATP. If we don’t add fuel to the body during exercise in the form of sports drinks or juices, for example, our body’s glycogen supply will start to diminish after 30 to 60 minutes. At this point fat from adipose tissue and protein from muscles are used to make ATP. As a result, performance, endurance and overall body composition will be compromised, as protein in muscle is broken down to create glucose.
Glycogen stores and protein are key to providing enough energy to sustain activity. The body actually gets stronger when it’s resting and recovering from a workout. This is when glycogen stores are being replaced and the muscles are being nourished. In order for the body to perform these tasks, three macronutrients are required: carbohydrates, protein and water.
Both carbohydrates and protein play an important role in weight loss and muscle growth. Carbohydrates help replenish glycogen stores within muscles, whereas protein re-hydrates and nourishes muscles to aid in repairing and rebuilding them.
Carbohydrates are strings of sugar that get broken down in our body into glucose. Glucose is critical in tissue maintenance, fat metabolism and central nervous system function. Carbohydrates are a key source of energy, providing four calories of energy per gram. When carbohydrates are broken down by the body, glucose is produced. How quickly carbohydrates get broken down depends on the type. Fruit juice and bran muffins both contain carbohydrates, but they’re on different ends of the energy spectrum. Glucose from the juice enters the blood stream quickly and initiates a fast and high insulin response that helps move nutrients into your muscle tissue.
Energy in the form of a bran muffin never makes it into the blood stream because of its indigestibility. The amount of carbohydrates needed to replenish glycogen stores depend on your activity level as well as your metabolism. Generally speaking, the more intense the exercise, the more carbohydrates you’ll need to avoid breaking down muscle.
Many diet regimes substantially decrease carbohydrate intake to achieve weight loss. However, without adequate carbohydrates, weight loss – especially in the beginning – is a result of glycogen depletion and muscle loss, not fat loss. Don’t fall into this trap! To ensure you’re losing fat, not muscle, you still need to consume enough carbohydrates to replenish glycogen reserves depleted from exercise.
Just as important as what you eat is when you eat. Whether you’re running on the treadmill (endurance) or lifting weights (power), the timing and amount of protein, carbohydrates and fat eaten before and after exercise affects performance and recovery – the processes of refuelling and repairing muscles. In fact, a study published by the American Physiological Society found the content of food consumed had a tremendous impact on the magnitude and duration of the metabolic responses for hours and even days after exercising, especially insulin sensitivity[2]. The general macronutrient breakdown for a power vs. endurance protocol is as follows:
Macronutrient Power Protocol Endurance Protocol
Carbohydrates 55% 65%
Protein 30% 25%
Fat 15% 10%
Generally speaking, before exercise carbohydrates are used to provide fuel. After exercise, your body will act as a sponge, readily absorbing carbohydrates to replace fuel burned and re-store glycogen, while protein (amino acids) repairs muscles. The percentages between these macronutrients will differ depending on the type of exercise.
The following is an example of a diet assessment of an athlete following a “power” protocol:
Time Nutrient Breakdown Example of food to consume
7:00 am Breakfast Low to medium glycemic carbs with protein (3:1 ratio) Bowl of oatmeal with an egg
9:00 am Training 1-1.5 hrs Water 500mL-1500 ml
10:30 am Post Workout High glycemic carbs with protein (2:1 ratio) Whey Protein 25-35g + 50-60g carbohydrate drink
12:30 pm Lunch Medium glycemic carbohydrates with protein and fat (2:1:1 ratio) Sweet potato smoothie and a banana
3:00 pm Snack Low glycemic carbohydrates with protein and fat (1:1:1 ratio) Almonds
6:00 pm Dinner Medium–low glycemic carbohydrates with protein and fat (1:1:1 ratio) Whole wheat pasta with meat
8:00 pm Snack Protein (slow release protein blend; 20-30 gram serving) Casein protein or whey mixed with yogurt
Don’t forget the water!
Muscles are approximately 70% water, and it’s also the main component in blood, which delivers oxygen, nutrients, hormones and other substances to our cells. Water also plays a protective role, keeping us hydrated and cushioning the joints and body from injury. To remain hydrated, drink two cups of water an hour or so before exercising, and sip one-half to one cup of water every 15 to 20 minutes, depending on the intensity and type of exercise you’re doing. Drink two cups of water immediately following exercise, and one cup every 15 minutes for three hours, again depending on the type and intensity of exercise. In fact, intense workouts can result in a loss of 2.5 liters of sweat per hour. Along with water, sodium is also lost in sweat – 3000 mg of sodium per liter of sweat. So if you’re exercising for more than 60 minutes, sports drinks should be considered to replace needed electrolytes.
A beverage with a 6% carbohydrate solution (about a ½ oz. of sugar per 18 fluid oz.) is ideal for fluid absorption and energy delivery to the muscles. If you don’t like the commercial sports drinks, try this homemade natural 6% carbohydrate recipe drink:
1 Tbsp. pure maple sugar
2 cups filtered water
¼ – ½ tsp sea salt (as a source of sodium, potassium, calcium, magnesium and other trace minerals)
½ cup coconut water (as a source of potassium, magnesium and natural sugar)
Remember, achieving an ideal body composition is more important that what any bathroom scale indicates. If you’re embarking on a new diet and exercise program, ensure that your goal includes a reduction in body fat and an increase in muscle mass. Increasing your muscle mass will ensure long-term success, and is vital to managing and sustaining your ideal weight and overall health.
Before introducing any changes to your diet, have a thorough medical evaluation and always obtain your doctor’s permission before beginning any type of exercise program.
