Creating a Calorie Deficit
The causes for obesity are multifactorial. We covered some of those factors in part one which you will find here. Today we will go over calories and exercise.
In theory, fat contains 9 kcal per gram, protein has 4 kcal, and carbohydrates have 4 kcal per gram.
How many calories do you need per day? You can calculate your needs using an online tool. In order to lose weight, you should aim for a caloric deficit of around 300 to 500 kcals per day. At the end of the week you should go for 1 to 2 lbs (0.45 to 1 kg). These numbers may seem low but maintaining this rate will make you lose at least 52 lbs (23.4 kg) after only one year.
The 3,500 kcal myth: The rule of thumb that in order to lose 1 pound or 454 g of fat, we need to burn 3,500 kcal is a myth. The calculation of 3,500 kcal is faulty when we know that fat can be 9.4 kcal per gram instead of just 9 (Kenney, Wilmore, & Costill, 2011). Harcombe (2011) argues that human fat tissue is 87% lipid, which would bring the calories to 3,555 kcal (454 x 9 x 87/100). She also cites the work of Bozenraad (1911), who also found fat in humans to be 72%. Even so, Hall, and Chow (2013) demonstrated that this rule does not take into account the dynamic changes in energy balance.
If counting calories is not your preference, you can opt for using your fists as a way to measure your portions: One fist-size portion of protein, two fists for fruits and vegetables, and one fist for starch.
How much exercise do you need? Minimum requirements according the American College of Sports Medicine (ACSM, 2011) are 150 minutes of cardiovascular exercise, two sessions of eight to ten resistance training (strength) exercises, 20 to 30 minutes of flexibility (stretching), and 60 minutes of neuromuscular training (balance and agility) per week. These guidelines may be overwhelming but just like the diet; they should be implemented progressively and appropriately to your level.
Is low-intensity cardio better for fat loss? Not really. Low-intensity cardiovascular exercise is considered to burn mostly fat but it does not necessarily affect the total calories expended for the same amount of time exercised. As a result you should aim to exercise at least at a moderate level to maximize burning fat. As a suggestion, on a scale from 1 (sitting on a couch) to 10 (about to throw up), with 4 being a leisurely walk, you should be around a 6 or 7.
We will have more insights on how to plan your resistance training in the coming weeks. In the meantime, feel free to ask us any questions on our Facebook page.
American College of Sports Medicine (2011). Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: Guidance for prescribing exercise. Medicine & Science in Sports and Exercise, 43(7), 1334-1359.
Harcombe, Z. (2011). 1 lb does not equal 3,500 calories. Retrieved from http://www.zoeharcombe.com/standalone/1lb-does-not-equal-3500-calories/
Kenny, L. W., Wilmore, J. H., & Costill, D. L. (2011). Physiology of sport and exercise (5th ed.). Champaign, IL: Human Kinetics.
Hall, K. D., & Chow, C. C. (2013). Why is the 3500 kcal per pound weight loss rule wrong? International Journal of Obesity, 37(12), 1614-1615.