Burn Calories While You Eat: The Thermic Effect of Food
When it comes to losing fat and building muscle, eating less food is not the answer to getting lean and cut. You already know that eating less slows your metabolism. Thousands of studies have shown that eating smaller meals more frequently cuts down on cravings, binges, low energy levels, endless suffering and hunger pangs. Dividing and conquering large helpings balances blood sugar levels, increases metabolism and burns fat like crazy. Want to know why?
Part of the secret to keeping your fat levels in check is to use the Thermic Effect of Food to your advantage. Thermic Effect of Food represents the energy required for the digestion, absorption, transport, metabolism and storage of all the foods you eat and accounts for approximately 10 per cent of daily caloric burn.
Originally this phenomenon was known as the Specific Dynamic Action (SDA) of food, but now it is more commonly referred to as the Thermic Effect of Food (TEF). It has long been known that when you put food inside your stomach, you get a boost of energy. After each meal, your metabolism goes up soon after you start eating and peaks two to three hours later as your body needs to do a tough job — to process the nutrients you supplied, digest them, metabolise and deliver to the needing tissues.
In short, turning food into energy creates heat and burns calories. So, eating itself is thermogenic. Each spoonful of caloric energy boosts your metabolism through the action on hormones, enzymes, and engagement of all body systems.
Calculating the thermic effect of meals
Your overall TEF can range between 2-3 per cent and up to 25-30 per cent depending on the size of the meal and the types of foods eaten. A general guideline to calculate the TEF you eat is to take your total calorie consumption and multiply that by 10 per cent to get the total get the number of calories. So, if you eat 100 calories, you can spend up to a quarter of these just to digest the food. Larger meals tend to have greater TEF than smaller portions.
Have you heard the saying that a ‘calorie is not a calorie’? It is true in two ways. First, some of the foods you eat are better used for energy (complex carbohydrates), others are more likely to be stored as fat (simple carbohydrates and fats), while others yet are best used for building new cells and tissues (proteins and essential fatty acids). Second, depending on what you eat, you might either speed up metabolism, satisfy hunger and get real-time energy or you might end up packing up calories in certain storage compartments and feel sleepy while remaining hungry — even if you stomach is full. Each calorie you get from fat is not digested and metabolised the same way as a calorie derived from carbohydrate or protein. This is because your body, being a smart machine, uses and stores all nutrients differently.
What matters is not how many calories you eat, but where these calories come from. You can burn more calories without depriving yourself of your favourite foods, you just need to learn how to combine the foods and in what proportions. If you eat the ‘normal’ mixture of nutrients, including proteins, carbohydrates and fats, your BMR will get a spike of around 10 per cent of the food’s energy content.
You’ll find it much easier to reduce your fat levels if you consume plenty of foods with a higher Thermic Effect. Now, which foods burn more calories?
Carbohydrates: TEF is 5-30 per cent.
You will always need at least some carbohydrate intake to keep your body moving and your metabolism roaring. Carbohydrates provide your body with the energy needed so that you can get the workout you need. They are energy source for your muscles, and without some carbs, you won’t be able to get in the type of workout you need to build muscle.
Carbohydrates are found in sugars, grains, fruit, vegetables, legumes, nuts and dairy, and give you immediate energy providing four calories per gram. This doesn’t mean that 100g of cooked pasta will give you 100g of carbohydrates (in fact, only around 25g). But 100g of sugar will give you 100g of carbohydrates. So, you need figure out the specific content of this nutrient in each food. So, if you eat a candy made of plain sugar, your body will actually get 90 calories, spending 10 on digestion.
Although all carbohydrates have four calories per gram, some carbohydrate-rich foods have a higher TEF. Fruits, vegetables, legumes, nuts, seeds and grains are healthier than sweets, soft drinks and pastries. Why? Fibrous fruits and vegetables have a TEF is about 20 per cent. These outstanding additions are loaded with vitamins and minerals, phytochemicals and antioxidants. Besides burning more calories than most other foods, veggies also help in the digestive process by stimulating various enzymes needed for proper nutrient absorption. Junk foods usually are poor sources of nutrients and sometimes we refer to these foods as having ‘empty’ calories. This means the foods have lots of calories with little or no nutrition. Get a good portion of vegetables in at least two-to-three of your six daily meals.
Fats: TEF is 0-5 per cent.
Let’s be clear: we need fat in our diet. It may be the least appealing nutrient from a dieter’s view, and that’s understandable. As the most concentrated source of energy, it provides nine calories per gram of fat compared with four calories per gram for protein and carbohydrates. Keeping certain levels of fats in your diet is necessary, but fats tend to be high in calories and have a low thermic effect. Fat has the lowest TEF and requires the least amount of energy to be digested. But if you eat fat, it may take hours before the fatty acids reach the blood stream, so they may keep your satiety levels up for many hours. The low-digesting fat lowers the glycemic index of any food you eat, doesn’t raise blood sugar levels and even limits the rise of the fat-storing hormone insulin, which you normally get from eating carbs or protein. In other words, eating fat is the only known natural way to curb your hunger and maintain blood sugar levels for many hours longer. Plus, eating fat has a great hormonal effect and has shown to actually boost your resting metabolism.
When chosen properly, fat can be your best ally in the war on body fat. Here comes the golden rule: it is not the quantity, but the quality of fat that really matters. Briefly, fats you eat can be classified as saturated, unsaturated and trans fatty acids. Saturated fats are derived from animal products such as meat, dairy and eggs, and are also found in some plant-based sources such as coconut, palm and palm kernel oils. They are solid at room temperature and melt when heated.
Monounsaturated and polyunsaturated fats are two types of unsaturated fatty acids derived from vegetables and plants. These are liquid at room temperature but begin to solidify at cold temperatures. You can find these in olives, olive oil, nuts, peanut oil, canola oil, avocados, safflower, sesame, corn, cottonseed and soybean oils.
Trans fats are actually unsaturated fats that go through hydrogenation, the chemical process that changes liquid oils into solid fats. They are found in commercial cakes, shortenings, spreads, and in some of the convenience foods.
How do you tell a good fat from a bad one? Apart from trans fats, which are probably the worst man-made foods ever created, there are no good fats and no bad fats. You need all of them; some more than others. The best fats come from unsaturated Essential Fatty Acids. Eat more liquid fats and less solid fats and you should be fine.
Proteins: TEF is 30 per cent.
Protein is probably the most complex macronutrient. The reason protein demands so much energy and has such a high metabolic cost can be found in all the hormones, enzymes and other metabolites involved in processing the amino acids.
Protein is found in all animal products, including red meat, poultry, eggs, dairy, fish, and also to a lesser degree in vegetable sources of grains, legumes, nuts and seeds. Just like carbohydrates, each gram of protein has four calories. However, the complete weight of protein-rich food is not exactly the same as the number of protein grams it contains. For example, 100g of lean fish translates only into around 25g of protein, while 100g of pure protein powder may give you all 100.
Animal sources of protein are ‘complete proteins’. That means that each protein found in an animal product contains each of the nine essential amino acids. Plant proteins are ‘incomplete proteins’. Each plant protein is missing at least one of the nine essential amino acids. However, every amino acid is found in some type of plant, so you can combine different plant proteins to get all of the amino acids you need. For example, combining legumes and grains is a great way to balance the missing amino acids and get the complete protein profile from plant foods. Soybeans, however, are the one exception. They are the only known plant food which contains complete protein and has one of the best protein digestibility ratings among all protein sources with little or no fat and cholesterol.
High protein foods are essential for muscle gain and fat loss. Think of these foods as your metabolic stimulators. They nuke a lot of calories just by being present in the tummy, and also slow down the release of carbs and fats into your bloodstream, helping maintain and build metabolically hungry muscles to keep your body lean and strong. Eat protein with every meal and snack, at least one gram of protein per kilo of body weight, spreading it evenly throughout the day.
Recommendations for thermogenic eating.
Just eat
Lesson number one: if you want to boost your metabolism, shrink your fat cells and have plenty of energy to build additional muscle mass, you must eat more. Period. When you eat less, exercising is not as enjoyable as you may not have enough energy to move. You need all nutrients. A sound diet should not only be varied and provide adequate nutrients throughout each day, it should be flexible and adaptable depending on what you like, what you have, and how you feel on a particular day.
For example, if it is your workout day, your body is under increased stress and you need to eat more protein, carbohydrates, certain vitamins, minerals and amino acids. This is, of course, if you strive for proper recuperation and getting some kind of positive results for all the hard work in the gym. Same thing applies if you are under emotional stress or ill. While food is certainly not the only consideration, it definitely is a large chunk.
You mind, hormones, neurochemicals, blood cells, immune cells, enzymes constantly cry for nourishment. This is why you need to eat around the clock. Changing your eating patterns can rev up metabolism and energy levels and give you the opportunity to enjoy delicious meals all day long and lose weight at the same time.
The usual recommendation is to drink eight cups (1.8L) of water daily, and more when you exercise — but the more ice-cold water you drink, the more calories you burn.
Spice it up a notch
Certain spices can give your fat loss an added zing. “Ginger, cloves, cayenne, coriander, bay leaves and dry mustard have all demonstrated a thermogenic, or fat-burning, effect, thus raising metabolism,” says Ann Louise Gittleman, author of The Fat Flush Plan. Another positive effect of consuming hot herbs is that they stimulate thirst, so you’ll drink more (water, that is!). Water for your body is like oil for your car. You need water for all bodily processes, including digestion, waste excretion, circulation and even breathing. Dehydration can lead to sugar cravings, fatigue, and an ill temper marked by edginess and cloudy thinking. As well, dehydration slows down fat-burning significantly and prevents the muscles from taking advantage of the carbs you’re eating.
Try sprinkling some cinnamon on your next non-fat latte. Researchers from the U.S. Department of Agriculture have shown that just a quarter of a teaspoon to one teaspoon of cinnamon taken with food can help boost metabolism twenty-fold. This extraordinary spice makes fat cells much more responsive to insulin, the hormone that regulates sugar.
Fibre
Fibre-rich foods are termed sometimes as ‘negative calorie’ foods because they burn more calories than they provide — at least in theory. Eat plenty of vegetables, particularly fibrous green leafy vegetables, two pieces of fruit and at least six servings of complex carbohydrates from whole grains with bran and germ best combined with the ultimate fibre sources — beans and legumes. A combination of these last two will not only heat up your metabolic rate, but will provide an additional protein boost because grains and legumes have complementary amino acids which turn into complete protein when eaten at the same time.
While fibre-rich foods are important, don’t overeat these foods in your diet. You still need the essentials — carbs, proteins and fats — to keep your system in optimal healthy balance.
It is virtually impossible to gain body fat with a diet that is very high in foods with a high Thermic Effect. Rely more heavily on these types of foods for fat loss, but keep all nutrients in place for weight gain and adding more muscle. This way you will keep your body in the positive energy balance allowing for growth.
Exercise — food hates it when you move.
Of course, you must stimulate growth by exercise. Training without good planning and nutritional support for building muscle mass is like bringing a bunch of construction workers to their site without tools and bricks. If you start to eat more and train less, as probably happens in the off-season and during holidays, you will grow. Specifically, you put yourself in a true anabolic state, grow muscles, improve your body composition, burn whatever leftover fat cells you have around your belly, and take your training above and beyond your expectations.
A simple increase in calories has shown to enhance the famous anabolic trio: growth hormone, testosterone and insulin-like growth factor-1 (IGF-1). On the flip side, when you start your cut-up season and starve yourself on another diet, the levels of these hormones drop and catabolism takes off.
A study published in the journal Medicine and Science in Sports and Exercise found that the Thermic Effect of a meal is 50 per cent greater in men who train with weights compared with men who are sedentary. Also, researchers from the Department of Kinesiology at the University of Nevada studied the effects of weight training on the Thermic Effect of Food. After they measured the metabolic rate of subjects who ate a high-carbohydrate meal containing 660 calories prior to weight training they found that the Thermic Effect or the energy expenditure was greater when compared to a different group of subjects who did not exercise but ate the same diet. In fact, the TEF was 73 per cent greater after the weight training trial than in the control trial. The researchers think part of this response is due to the energy cost of glycogen synthesis. If you train with weights on a regular basis you’ll burn off more of the calories you eat.
A study from Washington University School of Medicine also shows that the calories in a meal that are high in fat or sugar are less likely to be stored as fat if you eat them after exercise. The study shows that 60 minutes of exercise helps to ‘divert’ fat and sugar into muscle, rather than fat tissue. This may be possibly because exercise increases the activity of enzymes responsible for transporting sugar and fat into your muscles.
Of course, this doesn’t mean that exercise gives you the freedom to eat all you want. The key to losing body fat is to burn more calories than you get from your diet. The key to building lean mass is training, proper nutrient supply and sufficient recovery. If you simply replace the extra energy you’ve expended during exercise with additional calories from your diet, then your weight won’t change, but you may change your body composition by manipulating the nutrients.
References
Denzer, C.M., & Young, J.C. (2003). The effect of resistance exercise on the thermic effect of food. International Journal of Sports Nutrition and Exercise Metabolism, 13, 396-402.
Greiwe, J.S., Holloszy, J.O., & Semenkovich, C.F. (2000). Exercise induces lipoprotein lipase and GLUT-4 protein in muscle independent of adrenergic-receptor signaling. Journal of Applied Physiology, 89, 176-181.
Thyfault JP, Richmond SR, Carper MJ, Potteiger JA, & Hulver MW. (2004). Postprandial metabolism in resistance-trained versus sedentary males. Med Sci Sports Exerc, 36, 709-716. IM
