What is a calorie and how many calories should I eat to lose weight?

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  • To lose weight, you need to burn more calories than you eat. Sounds easy, right? But what is a calorie and many calories should you eat to lose weight? Here's how it works.

    If you want to know how to lose weight fast, firstly don’t imagine you’re going on a diet. The word conjures up images of restrictions and prohibitions around all the foods you love. It can set you up for failure before you’ve even started. ‘Oops I’ve eaten a chocolate biscuit. It’s all over, I’ll finish the packet.’

    Instead imagine you’re embarking on a lifestyle change. One that will make you feel healthy and confident.

    One of the simplest methods of how to lose weight is to count calories. The average woman needs to eat around 2000 calories to maintain her weight and around 1500 calories a day to lose weight.

    In very basic terms, if you want to know how to lose weight, you just need to burn more calories than you eat.

    However, Sana Khan nutritionalist and founder of Avicenna Wellbeing says: ‘The role of weight management is more complex than simply counting calories. Weight management is governed by various physiological aspects including hormones such as insulin, and cortisol, health conditions that can be affecting weight such as thyroid disease and so on.’

    So whilst calories play a part, do factor in other elements when embarking on a weight loss regime.

    What is a calorie?

    A calorie is simply a unit that measures the energy contained in food and drink. Calories are printed on the packets of pretty much all foods and drinks (and if they aren’t, it’s easy to look them up). Tot them up throughout the day and work out where you are without going over your desired amount.

    How to lose weight: how many calories should I eat to lose weight?

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    How many calories should I eat a day to lose two pounds a week?

    To lose one pound per week, you need to eat 3500 calories less than you normally do each week – or 500 calories less per day. This number is the same for everyone, regardless of weight. A pound of fat is equal to about 3,500 calories, so everyone must burn 3,500 more calories than they consume each week to lose a pound of fat.

    To lose two pounds per week, you’ll need to double that.

    Exactly how you do that depends on your preference and lifestyle. The important thing to bear in mind is that it needs to fit easily into your life so you stick to it, says GP Dr Melanie Wynne-Jones. ‘Find a long-term, healthier way of eating that satisfies you, is affordable, suits your lifestyle, and provides all the nutrients you need.’

    A 1,000-calorie a day diet should help you lose weight but still feel full and satisfied. But just making tweaks to how you eat can help with weight loss too.

    There are many easy ways to do this.

    1: Use a smaller plate. It’s an easy way to reduce portion sizes. And stick to three meals a day, says Dr Michael Mosley. ‘A common belief is that if you spread out your food into lots of small meals this will increase your metabolic rate, keep you less hungry and help you lose weight. That’s not true.’  In a recent study, researchers at the Institute for Clinical and Experimental Medicine in Prague found that regular-meal eaters lost more weight and inches around their waist than the “eat-little-and-often” snackers, despite consuming the same number of calories.

    2: Put one quarter back. You’ve filled your bowl with cereal/pasta/rice. Now take away a quarter and eat what’s left. Are you satisfied at the end? You’ve just reduced your portion size. It may feel harder at first, but your stomach will start to shrink over two to three days and will quickly readjust to feel satisfied with a smaller amount of food. Try smaller meals with just 200 or 300 calories for a tasty, light lunch.

    3: Eat more protein. Protein is filling and helps to reduce your appetite, fighting off those food cravings. Plus, it actually increases your metabolic rate, meaning your body starts to burn through calories faster. ‘Eat protein – and it early’, says Dr Mosley. That way you get those brilliant benefits for the whole day. For high protein foods, think eggs, tuna, nuts, chicken, fish, yoghurt, tofu, granola, even cheese and (yes!) peanut butter! Sana says: ‘Protein is your best friend. Protein keeps us fuller for longer, and post workout recovery, protein is essential to help support muscles.’

    4: Avoid taking in unnecessary calories from sugary drinks such as sodas, fruit juices and milkshakes. Sana adds that fizzy drinks and fruit juices can have lots of sugar and calories. ‘Therefore trying to limit both of these can help reduce calories in the diet.’

    5: Drink more water. Aim for eight glasses a day. This keeps your nicely hydrated so that it’s running efficiently. That alone can help you burn 96 more calories a day. It’s also a good idea to have a glass before a meal. This will help to fill you up and aid digestion. Drinking plenty of water also helps to prevent fluid retention, as your body starts to feel confident that you are providing it with enough and lets the excess fluid it’s been holding on to – go.

    6: Reduce your intake of carbs and sugars. We’re not suggesting you cut them out altogether. The NHS positively recommends them. Starchy foods, such as bread, rice, potatoes and pasta, provide slow and steady energy throughout the day. But choose the whole grain versions – and enjoy potatoes with their skins on. This not only adds fibre to your diet to keep things moving;  it also helps to make you feel full.

    7: Increase your fruit and veg: When making a lunch or dinner, the ‘thirds’ rule is best: one third protein, one third veg and one third carbs. Remember, when bread enters your system, it pretty much turns back into dough in your stomach. This is hard for your body to digest. Help it along with plenty of fresh fruit or veg. They’re packed with nutrients but not many calories, so tuck into them as often as you can! There is, however, quite a range in the number of calories in different fruits, so make sure you check them out.

    How to lose weight: how many calories should I eat to lose weight?

    Image: Getty

    Daily calorie intake calculator

    Many people keeping an eye on their calories use a calorie intake calculator to help them.

    The Harris-Benedict equation is the most popular one. It looks complicated but is actually pretty simple once you do the maths.

    To work out how many calories you need for weight loss, you work out your BMR – Basal Metabolic Rate. Here’s how you do it:

    Your BMR = 655 + (4.35 x your weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)

    You just need to plug in your age, height, and weight. The number you get at the end is the total number of calories you need each day to exist.

    So, a 40 year old woman who is 5ft 5ins and weighs 150 lbs has a basal metabolic rate of 1378.

    Next, you need to work out your activity factor. Your activity factor is the amount of exercise you do on a daily basis.

    Most people have an activity factor of 1.5. However, you can calculate yours by looking at the factors below:

    Sedentary: Minimal movement, lots of TV watching, reading, etc. Activity factor = 1.4
    Light activity: Office work, less than one hour of moderate exercise/activity during the day. Activity factor = 1.5
    Moderate activity: Light physical exercise/manual labour during the day, plus a more active lifestyle. Activity factor = 1.6
    Very Active: Active military, full-time athlete, hard physical/manual labour work. Activity factor = 1.9

    Choose your activity factor and multiply that by your BMR:

    So 1.5 x 1378 = 2,067

    This number is the number of calories you need to eat each day to maintain your weight. To lose weight, eat between 500 or 1000 calories less than this, depending on whether you want to lose one or two pounds a week.

    How to lose weight: how many calories should I eat to lose weight?

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    How many calories should I eat to lose weight with exercise?

    The average person burns around 1800 calories a day doing absolutely nothing. According to the Healthy Eating Guide, sitting burns an estimated 75 calories per hour.

    A sedentary woman aged 19 to 30 burns 1,800 to 2,000 calories daily, while a sedentary woman aged 31 to 51 burns about 1,800 calories per day.

    An active woman between 19 and 30 burns about 2,400 calories per day, while an active woman aged 31 to 51 burns about 2,200 calories.

    The number of actual calories burned, of course, depends on your body composition, weight and metabolism – and here’s where things get a bit complicated.

    For example, a 125-pound person will burn just 120 calories during a 30-minute walk at 3.5 miles per hour, while a 185-pound person will burn 178 calories during a walk of the same speed and length.

    If the same two people swam the front crawl for 30 minutes, the 125-pound person would burn 330 calories, and the 185-pound person would burn 488 calories.

    So, a heavier person will burn more calories than a slim person, but muscle burns more calories than fat. If a muscular person and an overweight person exercise at the same intensity, the muscular person will burn more calories than the overweight person.

    For simplicity, we will use an average weight person exercising for 30 minutes at a time to illustrate which activities are best at burning calories:

    Aerobics – 350 calories
    Skipping – 390 calories
    Rowing – 370 calories
    Skiing – 360 calories
    Running – 300 calories
    Swimming – 300 calories
    Playing tennis – 200 calories
    Walking – 150 calories

    And remember: it doesn’t have to be organised exercise, everyday activities help burn calories too. Everything from housework to gardening – even taking a bath!

    And even low-impact exercise can make a difference. Research from the Journal of Physical Activity and Health found that regular yoga helps lost weight stay off.  Researchers believe it’s not so much the physical energy expended, as yoga is relatively low-energy compared to other activities, but that those doing yoga develop better body awareness and stress management, leading to a healthier lifestyle and diet.

    READ MORE: 15 minute workouts to improve your strength, fitness and balance

    How to lose weight: how many calories should I eat to lose weight?

    Image: Getty

    Eight calorie counting weight loss tips

    If you choose the calorie-counting method to help you lose weight, there are lots of ways to make things nice and easy to help you along:

    1: Use a Fitbit: Fitbit provides a great ‘calorie burn’ estimate. It takes into account your BMR, the activity recorded by your tracker and any activities you log manually. Your tracker’s calorie count will reset each night at midnight and begin counting immediately thereafter. BMR is the reason your tracker starts the day with calories already burned — you still burn calories in your sleep.

    2: MyFitnessPal is one of the most popular calorie counters right now. It tracks your weight and calculates a recommended daily calorie intake. It also contains a well-designed food diary and an exercise log. If you’re using a fitness tracking device, MyFitnessPal can usually sync with it and then include the data in the exercise log.

    The app tracks your progress towards your goals and offers chat forums with fellow users. MyFitnessPal also has a barcode scanner, so you can also instantly enter the nutritional information of some packaged foods. Sana says whilst she doesn’t count calories, she does encourage people on weight loss programs to use apps such as My Fitness Pal to keep track of their food throughout the day. ‘Being mindful of the food you were having in a day can help any weight loss program simply because you are aware of how much and what you are consuming.’

    3: Bulk prep meals in advance. This will save time when it comes to working out the calories. Set aside a few hours once a month to put on your chef’s hat and have some fun cooking meals you like that can be portioned up and frozen. We have plenty of low calories meals to inspire you, including our 160 family meals under 500 calories, meals under 300 calories, and lunches under 200 calories just to get you started.

    4: Lose It is an app that puts the emphasis firmly on losing weight, as the name suggests. Like its rivals, it starts by getting you to set a goal: using your current and target weights, height, gender and desired pace of weight loss to assign a daily “budget” for your food intake.

    Graphs on your intake, nutrients and steps are very clear, while the process for logging your meals, snacks and exercise is quick and easy too, whether you’re searching for ingredients or scanning barcodes. The ability to browse menus from popular restaurant brands, from KFC to Nando’s, is also handy.

    They have an active chat community and a tab called ‘challenges’, where you can participate in challenges or make your own.

    Lose It is free at basic level, but premium tier costs £29.99 a year. It offers more tracking (hydration, sleep, body fat etc); more detailed nutritional reports; more features for meal and exercise planning, and a wider range of challenges including the ability to create your own.

    5: Get portion savvy. Even if you can’t or don’t want to tally the calories you eat at every single meal or snack, portion control is an easy way to help you consume fewer calories. Think of a tennis ball. It’s the equivalent of the recommended portion for items like pasta, cereal and yogurt.

    6: Don’t eat straight out of the container. It’s a recipe for mindlessly overeating. Instead, measure a serving size of whatever you’re noshing on — almonds, soy chips, or other snacks — and put it on a plate or in a bowl.

    7: Use smaller plates. This really is a great way to lose weight. Trick your mind into thinking that you have more food by downsizing your large dinner plate for a smaller, salad-sized one. A healthy portion can look tiny on a huge plate. However it will seem more normal when you shrink its surroundings. And spoil your appetite with nutritious low calories snacks. Try eating celery sticks with peanut butter an hour before lunch or dinner. You’ll eat less at the meal and feel more satisfied later.

    8: Limit your calories for each meal. A good guide is to keep breakfast under 100 calories, lunch under 200 calories, and dinner under 600 calories. Limit the number of snacks you have during the day. If you do have them, try to make sure they’re low-calorie snacks. There are also plenty of meal ideas under 300 calories so no need to get bored eating the same thing week after week. Also, research suggests that you may burn more calories at breakfast so if you’re struggling to lose weight try having more calories for breakfast and less for lunch or dinner.

    How many calories do I need to eat when breast-feeding?

    It’s perfectly safe to watch the calories while breastfeeding. But, make sure your total caloric intake doesn’t dip below 1,800 calories per day. Also, keep eating a wide variety of nutritious foods.

    Sana explains that mums who are breast feeding should ensure that they are eating lots of fresh fruit and vegetables. ‘As well as this, fibre, good quality fats and good quality protein help facilitate the production of breastmilk and the quality of the milk.’

    ‘My focus would be on eating small sized meals five times a day rather than large size meals less often. Keep your blood sugar levels balanced to ensure you have the energy for yourself and the baby.’

    According to the Centers for Disease Control and Prevention, an extra 450 to 500 calories is needed to help your body keep up the milk supply for your baby.

    Calorie counting: is it for you?

    Calorie counting might not be for everyone, but it is an easy-to-follow plan for those who want to restrict their calorie intake and exercise more to help them lose weight.

    Results can usually be seen pretty quickly and counting calories provides an easy structure to follow for those who don’t want to embark on faddy diet plans.

    Tracking calories is also a great way of becoming aware of bad habits (ie eating too many high calorie, sugary foods) while encouraging low-calorie, healthier alternatives.