Weight loss is essentially a math equation: You lose weight when your total energy intake (calories consumed) is less than your total energy expenditure (calories burned).
Total energy expenditure (TEE) is made up of resting energy expenditure (REE, what’s needed for basic body functions), the energy used during physical activity, and the energy used during digestion. By adjusting your diet and exercise routine, you can affect the number of calories consumed and/or expended to create a calorie deficit result in weight loss.
Lose 20 Pounds
To lose 20 pounds in two months, you have you lose about 2.5 pounds per week. According to the Centers for Disease Control and Prevention (CDC), healthy weight loss is in the range of 1-2 pounds per week, as people who lose weight gradually are more likely to keep it off.
However, it may be possible to achieve a 2.5 pound per week weight loss by eating smart and increasing physical activity. Consult a doctor if you have questions about what a healthy amount of weight loss is for you.
It has been widely believed that 3,500 calories are equal to 1 pound of weight. But an article in the December 2014 issue of the International Journal of Obesity found that the 3,500 calorie rule overestimates weight loss. Due to variations in factors including body composition, gender, age, height and amount of calorie restriction, weight loss is not linear like the 3,500 rule would predict.
Diet for Weight Loss
Not all calories are equal, so changing the composition of your caloric intake is important to losing weight.
In a review published in April 2015 in the American Journal of Clinical Nutrition, researchers concluded a higher-protein diet was linked to multiple benefits in weight loss. Increased protein is linked to increased energy expenditure, which can help you burn more calories. Protein is also more filling and effective in creating the feeling of satiety (or fullness) compared to carbohydrates or dietary fat, so incorporating more protein into your diet may help you eat fewer calories.
Eat Fewer Carbs
In an article in the November 2018 issue of the British Medical Journal, researchers found that participants on a low-carbohydrate diet (defined as 20 percent of total calories) had significant higher TEE than those on a high-carbohydrate diet (60 percent of total calories).
Carbohydrates are an important source of energy for your body, especially if you are physically active. To help lose 20 pounds in two months, you should try to limit refined carbohydrates such as white rice and pasta and focus on fiber-rich, complex carbohydrates such as beans and whole grains.
Consume Less Sugar
In a review and meta-analysis published in the British Medical Journal in January 2013, individuals who decreased their consumption of free sugars (sugars added to food as well as the natural sugars in honey, syrups and fruit juices) and sugar-sweetened beverages lost body weight. This was due to reductions in overall caloric intake; when subjects replaced high-sugar foods with low-sugar alternatives, the same body weight changes were not found.
In addition to being linked to obesity, eating too much sugar can also increase the risk of type 2 diabetes and heart disease. The CDC recommends adults limit their intake of added sugars to 10 percent of total calories.
Proper hydration is important for overall health and body function, but there is also some evidence that water can help you lose weight. In a study that appeared in the July 2016 issue of the Annals of Family Medicine, researchers found that increased inadequate hydration was linked to elevated BMI and obesity.
The daily recommended water intake (water from both food and beverages) is 91 ounces and 125 ounces for adult women and men, respectively. Individual needs vary by climate, age, gender and activity level.
Exercise for Weight Loss
The CDC recommends that adults who want to maintain their weight engage in 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic activity per week. This can be spread over the week and you can mix both moderate- and vigorous-intensity activities. To lose weight, you should increase this amount to help create a calorie deficit.
A moderate-intense activity is defined as an activity where breathing and heart rate are accelerated but you can still have a conversation. These could include a brisk walk or casual bike ride. A vigorous-intense activity is one where your heart rate is up and your breathing is hard. These include running, swimming laps, hiking uphill or high-intensity interval training (HIIT). The CDC has estimates of calories used in a variety of moderate and vigorous activities.