Sometimes you need to lose weight and lose it fast. An upcoming wedding, a class reunion, beach vacation or another important event can light the fire of motivation.
Or it even make you desperate to drop some pounds. For others, a recent doctor’s appointment or health scare may be motivating you to lose weight.
Regardless of your reason to lose weight, the bottom line is you want to change your body, lifestyle and habits. Once making some changes, you may be excited to get to know the “new you.”
Here at Livin3, we are excited to help you do just that! In this article, we will focus on how to lose those 20 pounds effectively, efficiently and in ample time. You will learn the best methods to lose weight and keep it off in the long term.
Let’s Get Started
You may think that you would rather do a fad diet to get the weight down rapidly, and then you’ll worry about how to keep it off. As a Registered Dietitian, I am here to tell you that weight loss must be done correctly from the start.
While you may be looking for fast weight loss, you might as well do it correctly and keep it off than do it too fast to sustain. But have no fear!
We will provide information on how you can start losing weight as soon as possible! In this post, you will learn exactly how to lose your 20 pounds based on science and tried-and-true methods.
One thing to note before we begin: Losing weight involves a variety of factors and variables that make it difficult to figure out how to lose a certain amount of weight in a limited amount of time. Weight loss is much more than “calories in equals calories out” or “a calorie is just a calorie.”
With our help at Livin3, you will learn the best weight loss strategies and main factors involved in losing the weight. You will also learn and how to reach your weight loss goals right on schedule. Let’s get started!
How Weight Loss Works
Weight loss seems simple: just burn more calories than you eat. The problem is, weight loss is not a one-size-fits-all process. What worked for your coworker or your sister will not necessarily work for you.
As frustrating as it is to watch your diet buddy shedding pounds while you’re at a weight plateau, it’s not their fault–or yours. Just like we all have unique personalities and faces, everybody’s metabolism is different, and responds to changes in diet and activity level in different ways.
Lifestyle and environment can be a factor here, too. Here are certain reasons your weight loss plan has to be individualized to your needs:
We all have different sizes and types of bodies.
While it may seem obvious, people sometimes believe that a celebrity’s weight loss journey, say after a C-section, is a direct reflection of how their weight loss journey should be.
Have you ever seen someone lose 20 pounds on a crash diet and then you were mad when you didn’t get the same results after you tried it? As with nearly anything related to health, nutrition and fitness, you can’t expect the same results as someone else.
With nearly half of Americans trying to lose weight, remember that age, race, gender, activity level and body composition are all factors that affect weight loss.
Caloric needs vary from person to person.
Why is it that some people can seemingly eat whatever they want and they can maintain their weight (or even lose weight)? Yet, when you look in the mirror, your body has stayed the same even though you have been trying to cut calories.
One huge reason diets with a set calorie amount, like the 3-day military diet, do not work for everyone is because we all have different calorie needs to lose weight. A single plan can’t fit everyone wanting to lose 20 pounds!
According to Harvard School of Medicine, men should consume no less than 1500 calories when trying to lose weight and women no less than 1200 calories (1). Consuming less than these amounts may actually deter weight loss!
Regardless, just because we have a minimum calorie amount established for each gender, does not mean that everyone should be consuming these minimum requirements. Depending on their age, activity level, height and health, someone may need to consume more than these minimum amounts, even for weight loss.
If someone else is able to lose weight on a 1700 calorie diet, you may need more or less calories to get the same results. To find your recommended calorie amount for weight loss, consult a registered dietitian. However, we have ways for you to estimate your calorie needs here.
We all have our own responsibilities.
The best weight loss plan is one that works seamlessly with your lifestyle. Even though a college kid may jump into weight loss by doing 2 workout sessions per day at the gym, a working single mom will not have that kind of time available. Find the weight loss plan that is practical for you.
Even our different leisure activities can affect our weight loss program. If you love playing video games after work, you are not burning substantial calories from weight loss doing that activity.
Thus, you would need to make extra time for physical activity. On the other hand, if you are a dancer trying to lose weight or lose 20 pounds, you can take the calories burned during rehearsal and add them to your total energy expenditure.
Understanding how your personal schedule affects your weekly calorie burn (or lack thereof) will help you determine how hard you need to work out at a commercial gym or in your home gym.
Consider the obstacles we face every day.
Many uncontrollable obstacles may be a factor in what foods to eat and how we get exercise. While a dietitian can tell a client what foods to eat for weight loss, the client will not be successful if they cannot access or afford those healthy foods.
People who do not have access to healthy foods may be living in a food desert. A food desert is a geographical location that lacks a grocery store and/or optimal food choices nearby.
Such locations tend to have lots of fast food and convenience stores that contain high fat, high sugar and low nutrient foods. People in these locations will have a hard time with weight loss if they only have junk food and fast food available.
Likewise, location can be an obstacle to getting enough exercise. For example, those who live in rural areas may not have sidewalks or parks to use for exercise and physical activity.
Areas in which the residents fear for their safety must also be considered when determining the best weight loss plan. If someone is not comfortable in their home or neighborhood, this can also prevent them from engaging in exercise and getting outside.
Do not underestimate financial challenges that affect weight loss.
While there is a common misconception that “healthy foods are expensive,” there are many ways to eat healthy on a budget. Regardless, while a celebrity could possibly afford a personal trainer, personal chef and personal dietitian, many others cannot afford such helpful services.
Likewise, while your aunt may be able to afford meal delivery services like Nutrisystem (which take the guesswork and effort out of weight loss), this may not be feasible for you. A weight loss plan should make you lose weight, not lose money!
We all have certain things we can’t live without.
In many instances, weight loss requires restriction or control of calories, foods and habits. While a good weight loss eating plan is inclusive of all foods, we may wish we can eat our favorite sugary, salty or fatty foods more often. It is normal to love certain foods and refuse to live without them!
For example, if you are a sweet tooth, you may need to have dessert every day, whereas someone else would be fine with omitting dessert to decrease calories. If your favorite food is pizza, you may gawk at limiting yourself to 1 pizza night per week, whereas someone else could successfully limit pizza to once per month without issue.
As you try to formulate your personalized weight loss plan, prioritize certain foods that you love and how you can still include them in the diet. Otherwise, you might go crazy without that favorite food (and binge on it later on).
Weight loss may seem like a simple concept, but reality makes it much more complex. What you eat, how much you exercise, your metabolism, current weight, lifestyle and more all come into play.
How to Achieve Weight Loss Success (and Lose 20 Pounds)
You probably know that losing weight involves changing your caloric balance. It sounds technical, but all it really means is that you expend more energy than you consume. In other words, it means that you need to eat fewer calories than you are using up.
You can change your caloric balance by eating fewer calories or by exercising more. A mixture of calorie control and exercise is a third option for reducing calories. See the example below to better understand weekly calorie deficits for weight loss.
Depending if you start out overweight or obese, your path to weight loss may vary. That being said, there are some basic rules about weight loss which are essential to understand if you want to lose 20 pounds.
Crunch the Numbers
To lose 1 pound, you need to burn 3500 calories. In other words, to lose 1 pound, you need to eliminate 3500 calories from your diet or burn them off by exercising.
If both of those sound pretty extreme, you can also choose to lose some of the 3500 calories by decreasing food calories and exercising off the rest. Here is a chart to show you how you can split up your calorie burn via diet and exercise.
Number of calories decreased per week
Number of calories burned via exercise per week
Total calorie deficit per week for 1 pound of weight loss
Calorie-only weight loss
|3500 (500 calorie deficit per day)||0||3500|
Exercise-only weight loss
|0||3500 (500 calorie burn per day)||3500|
Combination weight loss
|1750 (250 calorie deficit per day)||1750 (250 calorie burn per day)||3500|
Use this handy chart to see if you are on target for cutting out those 3500 calories weekly. Here is a real life example of counting calories for weight loss:
|Average Daily Calorie Intake Before Dieting||Average Calories Burned through Exercise While Dieting||Average Daily Calorie Intake While Dieting|
If you had been eating an average of say, 2000 calories a day before starting your diet and you drop back to about 1500 calories per day, then every day you’re cutting out 500 calories via diet.
Suppose you also exercise and burn about 250 calories per day. This brings you to a total daily caloric deficit of 750 calories compared to when you were not dieting. These changes can yield weight loss.
Please note: These calculations are for educational purposes only. Sustainable weight loss occurs at a rate of losing 1 to 2 pounds per week. This equates to losing 3500 to 7000 calories per week.
Know What You Have to Lose
Keep in mind that although we would all love to lose only fat, you may also lose some lean muscle and water. Also, if you are hoping to lose fat in certain areas, know that weight loss tends to shave off weight from all over your body. Too bad you can pick and choose where the weight loss occurs! That is what liposuction is for.
Losing weight is further complicated by metabolic changes that occur once you start to drop pounds. As you lose weight, your body typically consumes fewer calories at rest. Why? If you weigh less, there is less tissue to maintain. So that means as you lose weight, you have to work harder to continue to burn the same number of calories (2).
But, don’t be disheartened. We will outline how to lose those 20 pounds as soon as possible so that you can make progress in your weight loss journey. Now, let’s discover what it really takes to lose 20 pounds and how long you can expect it to take.
How Long Does it Take to Lose 20 Pounds?
It depends! Losing 20 pounds is quick work for some and challenging for others. There are a lot of factors that influence your current weight loss status. Here are some things to consider to accurately assess where you are at right now:
- How is your diet? If your diet isn’t the best for weight loss, making healthy changes may actually be pretty clear cut. For those who follow a generally healthy diet and still need to lose weight, there may be specific nuisances that are holding you back. See a registered dietitian for a customized nutrition plan.
- How often do you currently exercise each week? If you already exercise regularly, you may be ready to up the ante and really start losing weight. For those who rarely exercise, you will need to establish exercise consistency before you can start losing weight for the long term.
- Have you tried weight loss before? You may have some tricks up your sleeve if you have been successful in the past.
Now that you know where you’re at with the considerations above, let’s dive deeper into learning how to groom yourself in these areas so that you are able to start losing weight immediately!
Optimizing Your Diet for Weight Loss
The first step to start losing 20 pounds quickly is planning your diet. For the most success, strive to make a few simple changes, master them, and then move on to the next changes.
If you want to try a fast track to weight loss, try to make 3 to 4 simple dietary changes per week. For those who want a more moderate approach, try 1 to 2 changes per week. Keep reading for easy dietary changes you can start today.
Count Your Calories
Counting calories may seem a bit old-school, but it is one of the best ways to keep track of how much you are eating. If you see a registered dietitian, they will give you a specific calorie goal, otherwise, many food tracking apps can generate an estimated goal.
Remember: If you are a male, you should consume no less than 1500 calories per day. For females, consume no less than 1200 calories per day. For the easiest calorie counting, try a food tracking app.
Water is great because it hydrates your body, keeps you healthy, keeps you full and contains no calories! If you want to lose weight with minimal effort, replace your calorie-rich beverages with water.
In fact, one study found that replacing sugary beverages with water significantly reduced the weight of the participants (3). Furthermore, research shows that water helps increase your sense of fullness before eating, meaning you have better control over portion size.
Get Your Fiber
Similarly to how water can delay hunger, another weight loss tip is to make sure you are getting enough fiber. Fiber keeps you feeling full and keeps your bowels moving along regularly. Imagine how good you’d feel if you weren’t hungry and your daily bowel movements kept you feeling light!
Choose fiber-rich foods most often. Examples of fibrous foods include: fresh fruit, vegetables, whole grains, beans, nuts and legumes. Overall, the fuller you feel, the less calories you’ll crave (and the more weight you can potentially lose).
Get Enough Protein
Despite what you may see online from the fitness buffs, protein isn’t “life,” but it is a great tool to use for weight loss. Protein should make up about 25% of your overall diet. Just like water and fiber, protein can curb hunger for several hours.
While we can get protein from animals like cows and pigs, make sure you choose lean and preferred protein sources. Here is a list of the best protein sources to choose from if you are trying to be healthy and lose weight:
- Skinless chicken
- Lean turkey
- Beans and legumes
- Lowfat or skin milk, yogurt and cheese
Feel Full on Healthy Fats
Are you starting to catch a pattern here? For easier and successful weight loss, choose foods that keep you full! Healthy fats are yet another dietary component that you can use to keep you full, as long as you use it correctly. Since all fats have lots of calories, make sure you consume small amounts of healthy fats. Here are some examples:
- 1 Tbsp olive oil = 120 calories
- 4 oz salmon = 100 calories
- 1 Tbsp nuts = 45 calories
- ¼ avocado = 60 calories
- 2 Tbsp nut butter = 190 calories
Use Caffeine for a Kick
Tea and coffee are great to drink as part of your diet, as long as you minimize the amount of sugar, cream, honey or syrups you add. Alone, coffee and tea are low-calorie drinks that offer a caffeine kick to get you into motion.
Caffeine gives your metabolism a boost, helping you burn more calories than you would without caffeine, which is helpful for weight loss (4). Keep in mind, however, that too much caffeine can be dehydrating and prevent you from sleeping well! Limit overall caffeine consumption to no more than 400mg per day.
Choose Low-Calorie Foods
Low calorie foods are great for weight loss! Refer back to this list as needed when you are looking to munch on something but don’t want too many calories. To make sure you always have low calorie foods at home, add them to your shopping list each week. Here are some great low calorie options and their estimated calories:
- Celery: 1 stalk = 10 calories
- Blueberries: 1 cup = 85 calories
- Bok Choy: 1 cup = 30 calories
- Baby Carrots: ½ cup = 50 calories
- Cucumber: ½ a cucumber = 10 calories
- Egg White: 1 large egg white = 20 calories
- Spinach: 2 cups = 20 calories
- Tomato: 1 medium tomato = 25 calories
- Watermelon: 1 cup = 50 calories
- Peach: 1 medium fruit = 45 calories
Another important lesson when learning how to lose 20 pounds is portion size. You must adjust your portion size to meet your caloric goals. Many people find it helpful to use a smaller plate so that you aren’t tempted to fill up a larger one.
After all, even if you eat healthy, you can still overconsume calories! Use this portion size guide for reference. These portions can help you control your calorie intake.
Cook at Home
When you’re counting calories, cook for yourself. That way you can control how the foods are prepared, what’s in your meal and how much you make. In general, fast food and/or restaurant food tends to consist of larger portions, more calories, higher fat content, higher sodium and less overall nutrition. Cooking at home gives you control of your diet.
Decrease Sugar-Sweetened Beverages
When dieting, many people often focus on what to eat or what not to eat. However, they forget about the many calories consumed when drinking fruit juices, lemonade, soda, sports drinks and sweetened tea or coffee. Here’s the bottom line: Avoid drinking your calories if you’re trying to lose weight.
Many of the high-calorie beverages we mentioned also contain lots of sugar. When you look on the nutrition label on the bottle, you will see sugar listed in “grams.”
To better understand how much sugar is in that drink, convert grams to teaspoons. In order to do this, take the number of grams on the bottle and divide it by 4. This will tell you how many teaspoons are in a serving of that drink. Try it next time you see a regular soda. You may be really surprised!
Need Some Structure? Follow a Good Diet Plan
Some people need a little extra structure and support to be successful with weight loss. If you feel overwhelmed at the thought of implementing the diet tips listed above, look into following an existing diet plan.
A word of advice: Don’t always believe everything you hear about a diet plan. There is a plethora of bad, extreme, restrictive and downright inaccurate diets that you can fall into.
Here are several dietitian-approved diet plans to try. These specific plans were selected based on practically, inclusiveness of most foods and healthy dietary emphasis. With these diet plans, slow, steady and sustainable weight loss wins the race.
- DASH diet*
- Mediterranean diet*
- MIND diet*
- Weight Watchers
- TLC diet*
- Volumetrics diet
- Mayo Clinic diet*
- Jenny Craig (a meal-delivery service)
- Spark Solution diet
- Engine 2 diet*
- Nutrisystem (a meal-delivery service)
- Slim Fast (utilizes meal replacements)
- Health Management Resources (HMR) diet
- Medifast (utilizes meal replacements)
*Indicates diet should be coupled with your current calorie restriction.
Exercising to Lose Weight
The more you move, the more calories you burn, so include exercise in your weight loss plans! If you choose to restrict your diet substantially, don’t overdo the exercise, otherwise you could be putting your body into starvation and survival mode! Such states of extreme physical and metabolically stress can actually deter weight loss.
How to Choose the Best Exercise for You
Before starting any exercise routine, make sure to talk to your doctor. You may have certain exercise limitations based on your current health, previous injury and underlying conditions.
Also, jumping into a vigorous exercise routine can cause injury, ultimately postponing your weight loss journey. Who wants that? Once you are approved for exercise, we have some considerations on how to choose a good exercise plan for you:
How often will you exercise?
Certain exercises like HIIT training and spinning may not be best for people who want to work out daily. Pilates and yoga can be used as rest days for effective yet low impact exercise. That being said, the more vigorously you exercise, the more calories you’ll burn.
Do you have exercise restrictions?
If you have a previous injury or certain health conditions, some activity may not be suitable for you. For those with knee injuries, low impact cardio machines may be best.
Cardio, strength or both?
While a mixture of both cardio and strength is preferred for a well-rounded workout, you may need to prioritize one over the other based on time, limitations and fitness needs. In general, if you want to drop the pounds, choose cardio. If you want toning, engage in strength training.
Where will you exercise?
Some people prefer a commercial gym, others outside and yet others preferring to create a home fitness space. If you are looking to create a great home gym.
What motivates you to exercise?
Work on your motivation to exercise by working out with a friend or promising to reward yourself with a hot bubble bath when you’re done. Always reward yourself with a non-food reward.
When establishing an exercise routine for weight loss, choose an activity that fits your current fitness level, fits your lifestyle and is safe.
Burning Calories During Exercise
The name of the game for weight loss is calorie burn. According to the American Heart Association, those who are trying to lose weight should strive to get at least 300 minutes of moderate-intensity exercise per week. So, if you exercised for 60 minutes 5 days per week, you would be meeting that mark.
Here are some calorie estimates of how many calories you can burn in one hour of exercise. These numbers will vary based on several factors.
- Bicycling on a stationary bike at a moderate pace: 520 calories
- Walking at about 4 miles per hour: 335 calories
- Swimming: 445 calories
- Bicycling: 595 calories
- Running/jogging at about 6.7 mph: 820 calories
- Gardening: 335 calories
As you can see, you can make a lot of progress in a one-hour workout! If you are also controlling your calorie intake, strive to burn 500 calories per workout in order to lose weight.
Remember to always stop if you feel light-headed or faint during exercise. By listening to your body, you can reach your full exercise and dieting potential without causing yourself injury or harm.
Your Full-Proof Plan for Losing 20 Pounds in a Hurry
Now you have a multitude of tips to help you lose 20 pounds. You have all the tools that you need in your toolbox to plan and execute your own unique method for losing 20 pounds fast. So, how should you go about it?
First, carefully plan the time period during which you’re planning to lose the weight. You’ll want to make sure you don’t have any big events or special dates during your diet.
Why? Let’s face it: People usually celebrate with food. This can make sticking with your diet extra challenging. So, try to find a few weeks where you can cook for yourself or pack a lunch the whole time.
Next, choose which dietary changes you want to make. These changes could be the simple tips we discussed or choosing one of the preferred, dietitian-approved diet plans to model.
Regardless of which route you choose, pick a start date and stick to it. For most weight loss plans, you will need to plan each breakfast, snack, lunch and dinner.
You may also need to meal prep (typically on the weekend) and grocery shop, so make sure you schedule these tasks each week. While you’re busy doing all of these things, make sure you are still watching your calories.
Get Started Now: 2-Day Meal Plan
Here’s a sample 2-day weight loss meal plan to help get you started. As you will see, these meal plans are loaded with lean protein, fiber and healthy fats to keep you full.
- Breakfast: 1 cup 1% milk + 1 banana + 1 slice Ezekiel bread + 1 tsp spreadable whipped butter
- Lunch: 3/4 cup quinoa, cooked (after cooking) + 3/4 cup spinach + 1/2 cup chickpeas + 3oz chicken (cubed) + fresh herbs & lemon juice to taste
- Dinner: 6oz salmon fillet + 6 spears asparagus + 1/2 cup roasted zucchini + 1 slice Ezequiel bread
- Snack: 1 hardboiled egg
- Breakfast: 1 cup nonfat Greek yogurt (plain) + 2 Tbsp chia seeds + 1/2 cup fruit (i.e. berries, citrus) + 1/4 cup nuts (i.e. pistachios)
- Lunch: 2 low fat string cheese + 1 serving multigrain crackers (i.e. Special K Multi Grain crackers) + 2/3 cup dark berries + 2 Tbsp hummus
- Dinner: 4oz chicken + 3/4 cup quinoa, cooked (after cooking) + 1 cup Brussels sprouts
- Snack: ½ cup ice cream + ¼ cup fresh blueberries (or other dark berry)
Meal Plan Notes: Remember to drink plenty of water throughout the day, and tea and coffee in moderation. If you can dedicate yourself to planning out each day like this, you’ll thank yourself in the long run. When you have a plan in place, you’re less likely to give in to a craving or go off and eat something that could deter weight loss.
Get Started Now: Go Shopping
With your meal plan in place, it’s time to shop! We’ve compiled some grocery shopping tips so you can win at the grocery store:
- Make a list. Go ahead and make a grocery list based on your meal plan. Making a list will help you buy only the things on your list and avoid buying other tempting foods.
- Don’t shop hungry. You’re not yourself when you’re hungry! You also don’t make the best decisions when you’re hungry. Eat a meal or snack before you go to the grocery store to stay focused on the future.
- Head to the produce section first. Before you get tired and skimp over the fresh fruits and vegetables at the end of your grocery trip, head there first. Plan your meals around what is in season and cheap in the produce section.
- Purchase whole grains. Whole grains are loaded with fiber, vitamins and minerals. When you flip over a grain item (i.e. bread, pasta, tortilla), make sure the first ingredient on the ingredients list is “whole wheat flour” or “whole grain flour.” This tells you that it is made of whole grains. Choose whole grains more often.
Keep Up the Success: Check-in with Yourself
If you’re one of those people who have tried and failed to lose weight over and over again, you may fear failure (or worse yet, weight loss with subsequent weight regain). There are several things you can do to make sure you stay on track (or get back on track):
- Expect imperfection. Everyone makes mistakes, but not everyone learns from them. Allow yourself to have setback in your weight loss journey, but get back on the wagon as soon as possible.
- Weigh yourself regularly. Unless you suffer from an eating disorder, most people do well with weighing themselves once per week. When you do weigh yourself, make sure you record the weights. Also, make sure you weigh yourself at the same time on the same scale with the same clothes. This will give you the most accurate weight.
- Be honest with yourself. We usually know when we did or did not meet our dietary and exercise goals. Instead of making excuses as to why you didn’t work out this week, change your behavior and make it happen. Simple as that.
- Revisit your exercise and diet plan. As time goes on, things change. Things that were working for you at the start of your weight loss plan may not be practical as time goes on. Strive to revisit your diet and exercise plan once every 90 days.
Losing 20 Pounds Fast in A Nutshell
The bottom line on losing 20 pounds? You have to do 3 main things:
- Restrict calories and make lasting dietary changes
- Exercise consistently and safely while staying motivated
- Assess and reassess periodically to stay on track and troubleshoot when you have obstacles
Although weight loss may seem like a daunting task, with hard work and determination it is possible. Plan carefully and prepare yourself mentally. Before you know it, you’ll be ready for bathing suit season or that special event you’ve been preparing for.
What about after the diet? After you’ve done all that work to learn how to lose those 20 pounds, the last thing you want is for it to come right back on again. The important thing to remember is that even after your period of dieting and exercise, your job isn’t done. The weight loss journey is continual and lifelong.
Try to lead a healthy lifestyle afterwards by following a sustainable, calorie-controlled diet plan and doable exercise regimen. Continue to stay motivated to exercise for weight management and overall health. With lifelong modifications to your lifestyle, you can keep the weight off and enjoy the benefits for the long term.
Have you had great success with weight loss? We’d love to hear about your weight loss story. Tell us all about what worked (and what didn’t work). Have you tried crazy exercise or diet regimens? Share your story in the comments below. Your experiences may help someone else who is trying to lose weight!
- Calorie counting made easy. Harvard Health Publishing, 11 July 2020.
- Johannsen, Darcy L. et. al. Metabolic Slowing with Massive Weight Loss despite Preservation of Fat-Free Mass. The Journal of Clinical Endocrinology & Metabolism, 24 April 2012.
- Nur Islami Mohd Fahmi Teng. Replacing Sugar Sweetened Beverages with Plain Water Improves Body Composition among Female Youth. Research Gate, August 2017.
- D Icken, S Feller, and S Engeli, et. al. Caffeine intake is related to successful weight loss maintenance. European Journal of Clinical Nutrition, 11 November 2015.
- Ducharme, Jamie. About Half of Americans Say They’re Trying to Lose Weight. Time, 12 July 2018.
- Counting calories: Get back to weight-loss basics. Mayo Clinic.