Whether you want to lose weight for a special occasion or simply improve your health, weight loss is a common goal.
To set realistic expectations, you may want to know a healthy weight loss rate.
How does weight loss happen?
Weight loss occurs when you consistently consume fewer calories than you burn each day.
Conversely, weight gain occurs when you consistently eat more calories than you burn.
Any food or drink that you consume that contains calories counts towards your total calorie intake.
However, the number of calories you burn each day, known as energy or calorie expenditure, is a bit more complicated.
Calorie expenditure consists of the following three main components:
Resting metabolic rate (RMR). This is the number of calories your body needs to maintain normal bodily functions, such as breathing and pumping blood.
Thermal effect of food (TEF). This refers to the calories used to digest, absorb, and metabolize food.
Thermal effect of activity (TEA). These are the calories you use during exercise. TEA can also include non-exercise activity thermogenesis (NEAT), which represents calories used in activities such as yard work and fidgeting.
If the number of calories you consume equals the number of calories you burn, you are maintaining your body weight.
If you want to lose weight, you must create a negative calorie balance by consuming fewer calories than you burn or burning more calories through increased activity.
Factors affecting weight loss
There are several factors that affect the rate of weight loss. Many of them are out of your control.
gender
The ratio of fat to muscle greatly affects your ability to lose weight.
Since women have higher fat to muscle ratio than men, their RMR is 5-10% lower than men of the same height.
This means that women burn 5-10% fewer calories than men at rest. Thus, men tend to lose weight faster than women on an equal calorie diet.
For example, an 8-week study of more than 2,000 participants on an 800-calorie diet found that men lost 16% more weight than women, with a relative weight loss of 11.8% in men and 10.3% in women.
However, while men tend to lose weight faster than women, the study did not analyze gender differences in the ability to maintain weight loss.
Age
One of the many physical changes that occur with age are changes in body composition – fat mass increases and muscle mass decreases.
This change, along with other factors such as the lower caloric needs of your key organs, contribute to a lower RMR.
In fact, adults over the age of 70 can have an RMR of 20-25% lower than younger adults.
This decrease in heart rate can make it more difficult to lose weight with age.
Starting point
Your initial body mass and composition may also affect how quickly you can expect to lose weight.
It is important to understand that different absolute weight loss (in pounds) can correspond to the same relative weight loss (%) in different individuals. In the end, losing weight is a complex process.
The Body Weight Chart from the National Institutes of Health (NIH) is a helpful guide to how much you can lose based on your starting weight, your age, your gender, and the number of calories you eat and expend.
Although a heavier person may lose twice as much weight, a lighter person may lose an equal percentage of their weight (10/250 = 4% vs. 5/125 = 4%).
For example, a person who weighs 300 pounds (136 kg) may lose 10 pounds (4.5 kg) after decreasing their daily intake by 1,000 calories and increasing physical activity for two weeks.
Calorie deficiency
A negative calorie balance must be created to lose weight. The extent of this calorie deficit affects how quickly you lose weight.
For example, consuming 500 fewer calories per day for 8 weeks is more likely to result in more weight loss than eating 200 fewer calories per day.
However, make sure not to make your calorie deficit too large.
Not only would doing so be unsustainable, but it would also put you at risk of nutrient deficiencies. Furthermore, it may make you more likely to lose weight in the form of muscle mass rather than fat mass.
Sleep
Sleep tends to be a neglected component of weight loss.
Chronic sleep loss can greatly hinder weight loss and the speed with which you shed pounds.
One night’s sleep deprivation has been shown to increase your desire to eat high-calorie and nutrient-poor foods, such as crackers, cakes, sugary drinks and chips.
One two-week study randomized participants to a calorie-restricted diet to sleep either 5.5 or 8.5 hours each night.
Those who slept 5.5 hours lost 55% less body fat and 60% more lean body mass than those who slept 8.5 hours per night.
Thus, chronic sleep deprivation is closely associated with type 2 diabetes, obesity, heart disease, and certain types of cancer.
Other factors
Several other factors can affect the rate of weight loss, including:
pharmaceutical. Many medications, such as antidepressants and other antipsychotics, can promote weight gain or hinder weight loss.
Medical cases. Illnesses, including depression and hypothyroidism, a condition in which the thyroid gland produces too few hormones that regulate metabolism, can slow weight loss and encourage weight gain.
Family history and genes. There is a well-established genetic component associated with people who are overweight or obese, and it may influence weight loss.
Follow a yo-yo diet. This pattern of weight loss and regain can make it more difficult to lose weight with each attempt due to the lower RMR