Introduction
Obesity has reached epidemic levels globally, with over 650 million adults worldwide being obese according to the World Health Organization (https://www.hsph.harvard.edu/obesity-prevention-source/obesity-rates-worldwide/). In the United States, obesity rates have continued to climb over the past decade, especially among men and some minority groups (https://www.forbes.com/health/weight-loss/obesity-statistics/). Obesity significantly increases the risk for serious health conditions like heart disease, type 2 diabetes, stroke, and certain cancers.
Losing weight can dramatically improve health and quality of life. Even a 5-10% weight loss for someone who is obese can provide meaningful health benefits. That's why it's critical for those struggling with obesity to understand the scientifically proven methods for sustainable weight loss.
Understanding Obesity
Obesity is defined as having an excessive amount of body fat. It is diagnosed when someone has a body mass index (BMI) of 30 or higher (1). BMI is calculated using a person's weight and height. A BMI between 25 and 29.9 is considered overweight. Having a BMI of 30 or higher puts someone at risk for health problems like heart disease, diabetes, and certain cancers. Obesity rates have been rising around the world. In the United States, around 40% of adults are obese (1).
Obesity is caused by an energy imbalance. This means the calories consumed are greater than the calories expended over time through metabolism and physical activity. Genetics, lifestyle factors, health conditions, and medications can also play a role in obesity. Consuming too many high-calorie foods and beverages and not being physically active enough contribute to weight gain over time (1).
(1) https://slideplayer.com/slide/6353222/Causes of Obesity
Obesity is a complex health condition with multiple contributing factors. Some of the main causes include:
Lifestyle Factors
Eating too many calories and not getting enough physical activity are key lifestyle factors that contribute to obesity. Consuming high-calorie foods like processed snacks, sugary drinks, and large portion sizes coupled with a sedentary lifestyle leads to an energy imbalance where you take in more calories than you burn off (1). This causes the excess calories to be stored as fat in the body over time, resulting in weight gain and obesity.
Genetics
Your genes can influence how your body regulates appetite and how it stores and processes fat. While genes alone do not cause obesity, they can increase your susceptibility to gaining weight (2). People with genes that predispose them to obesity may be more likely to become obese in an environment where high-calorie food is abundant and physical activity is limited.
Health Conditions
Certain health conditions like hypothyroidism, Cushing's syndrome, and polycystic ovary syndrome can disrupt the body's normal hormonal balance and metabolism, increasing the risk for obesity. Some medications used to treat conditions like depression, diabetes, and high blood pressure may also lead to weight gain as a side effect (3).
(1) https://www.healthline.com/nutrition/10-causes-of-weight-gain
(2) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3489947/
(3) https://www.healthline.com/nutrition/10-causes-of-weight-gain
Calorie Deficit for Weight Loss
A calorie deficit is when you consume fewer calories than your body burns in a day (1). To lose weight, you need to be in a calorie deficit so your body taps into stored fat for energy. A deficit of 500 calories per day should result in 1 pound of weight loss per week. Larger deficits lead to faster weight loss, but should not exceed 1000 calories per day for safety (2).
To calculate your calorie deficit: 1. Determine your maintenance calories - the amount you need to maintain your current weight. This depends on your age, sex, height, weight and activity level. Online calculators can estimate this (3). 2. Subtract 500-1000 calories to determine your calorie deficit for weight loss. 3. Consume fewer calories than your maintenance amount each day to create the deficit.
A calorie deficit forces your body to burn stored fat. Combined with exercise, a calorie deficit is the most effective and scientifically-proven way to lose weight sustainably.
Calculating Your Calorie Needs
Determining your daily calorie needs is an important first step for successful weight loss. There are a few methods to calculate your calorie expenditure:
Basal Metabolic Rate (BMR) - This estimates the minimum calories needed to sustain vital bodily functions at rest. An online BMR calculator requires inputs like age, height, weight and gender. BMR forms the baseline for determining calorie needs.[1]
Activity Level - Your total daily energy expenditure is higher than BMR due to physical activity. Multiplying BMR by an activity factor like 1.2-1.9 gives a rough calorie estimate for your lifestyle.[2]
Adjusted Body Weight - This formula accounts for higher calorie needs if overweight. It adjusts weight to calculate expenditure for an ideal body weight instead.[3]
To lose weight, you need a calorie deficit by consuming less energy than expended daily. A deficit of 500-1000 calories/day from your calculated needs causes steady weight loss.
Creating a Calorie Deficit
A calorie deficit is required for weight loss. A calorie deficit means you consume fewer calories than you burn. There are two main ways to create a calorie deficit:
1. Reduce calorie intake through diet - Eat fewer calories by reducing portion sizes, choosing lower calorie foods, and avoiding high calorie foods and drinks. Some tips include:
- Fill up on vegetables, fruits, whole grains, and lean proteins which are nutritious and lower in calories.
- Avoid added sugars, refined carbs, and unhealthy fats which are high in calories.
- Drink water instead of sugary drinks.
- Control portions by using smaller plates and not going back for seconds.
2. Increase calorie burn through exercise - Burn more calories by adding physical activity into your routine. Some suggestions include:
- Go for a walk, run, swim, bike ride, or do other cardio exercise most days of the week.
- Lift weights or do bodyweight exercises like pushups and squats to build muscle and rev up metabolism.
- Take the stairs instead of the elevator.
- Park farther away and walk.
- Stand and pace while on phone calls.
Combining a reduced calorie diet with increased physical activity creates the calorie deficit needed for weight loss. Aim for a 500-1000 calorie per day deficit to lose about 1-2 pounds per week safely and sustainably. Use a calorie deficit calculator to determine your needs.
Healthy Eating Tips
Here are some healthy eating tips to promote weight loss:
Focus on nutrient-dense foods like fruits, vegetables, whole grains, lean protein, and healthy fats. These provide vitamins, minerals, fiber, and other nutrients to keep you feeling satisfied (source).
Watch your portions and avoid overeating. Use a smaller plate, don't take seconds, and stop eating when you feel 80% full (source).
Meal prep and plan your meals in advance. This helps control portions and makes healthy eating more convenient (source).
Choose healthy cooking methods like baking, broiling, grilling, and steaming. Avoid frying foods which can add excess calories.
Read nutrition labels and be aware of calories, fat, sodium, and sugar in packaged foods.
Exercise Strategies
Exercise is a crucial component of long-term weight loss. Combining a healthy diet with regular physical activity is the most effective way to lose weight and keep it off (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2639700/).
For weight loss, experts recommend getting 150-300 minutes of moderate intensity exercise per week. Moderate intensity exercise includes brisk walking, swimming, cycling, or any activity that noticeably raises your heart rate. Aim for 30-60 minutes per day if possible (https://health.clevelandclinic.org/weight-loss-how-to-shed-10-pounds-for-good/).
In addition to cardio, it's important to incorporate strength training 2-3 times per week. Strength training builds lean muscle mass which boosts metabolism. Try bodyweight exercises, resistance bands, or weights. Yoga and pilates can also build core strength and flexibility.
Other forms of activity like taking the stairs, gardening, or cleaning also contribute. The key is to stay active as much as possible and find exercises you enjoy.
Overcoming Obstacles
Losing weight can be challenging, and it's common to encounter obstacles along the way. Some of the most common obstacles include plateaus, cravings, and motivation.
Hitting a weight loss plateau can be frustrating, but they are usually temporary. Plateaus happen when your body adapts to your diet and exercise regimen. To push past a plateau, you may need to adjust your calorie intake, increase exercise, or make other lifestyle changes (source). Patience and persistence are key.
Food cravings can also derail progress. To control cravings, make sure you are eating balanced meals so you don't get overly hungry. Stay hydrated, get enough sleep, and manage stress. If you get a craving, distract yourself with an activity or wait it out. Giving into cravings can trigger more cravings (source).
Maintaining motivation over the long-term is crucial. Set mini goals along the way and reward yourself when you reach them. Track your progress with photos, measurements, or an app. Enlist friends and family to support you. Remind yourself of the health benefits of weight loss to stay focused when you want to give up.
Maintaining Weight Loss
Losing weight is challenging, but keeping weight off long-term can be even harder. However, with some key lifestyle changes, permanent weight loss is absolutely possible.
One of the most important factors for maintaining weight loss is daily physical activity. Studies show that exercise helps stabilize weight loss by burning calories and building muscle (https://www.ncbi.nlm.nih.gov/books/NBK221839/). Aim for 150-300 minutes of moderate exercise per week, like brisk walking, swimming, or cycling. Even non-vigorous exercise can be beneficial.
It's also essential to continue monitoring your calorie intake after reaching your goal weight. Re-evaluate your daily needs and stick to a modest calorie deficit. Portion control and eating nutrient-dense whole foods will help keep you feeling full on fewer calories.
Developing healthy eating habits is critical as well. Eat slowly, minimize snacking and junk food, and focus on balanced meals with lean protein, produce, and whole grains. Meal prepping can help you stay on track.
Maintaining weight loss requires lifestyle changes you can sustain long-term. With regular exercise, mindful eating, and calorie awareness, permanent healthy weight is absolutely achievable.
