How long does it take to lose weight?

Combien de temps faut-il pour perdre du poids ?

Whether you want to lose weight for a special occasion or simply want to improve your health, weight loss is a common goal.

To set realistic expectations, you may want to know what a healthy weight loss rate is.

This article explains the factors that affect how long it will take you to lose weight .

How Weight Loss Happens

Weight loss occurs when you regularly consume fewer calories than you burn each day.

Conversely, weight gain is produced when you regularly eat more calories than you burn.

Any food or drink you consume that contains calories counts towards your overall calorie intake.

That said, the number of calories you burn each day, known as energy or calorie expenditure, is a bit more complicated.

Calorie expenditure is made up 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.
  • Thermic effect of food (TEF). This refers to the calories used to digest, absorb and metabolize food.
  • Thermic Activity Effect (TEA). These are the calories you use during exercise. TEA may also include non-exercise activity thermogenesis (NEAT), which accounts for calories used for activities such as yard work and restlessness.

If the number of calories you eat equals the number of calories you burn, you will maintain your body weight.

If you want to lose weight , you must create a negative calorie balance by consuming fewer calories than you burn or by burning more calories through increased activity.

Factors Affecting Weight Loss

Several factors affect the rate at which you lose weight. Many of them are out of control.


Your fat to muscle ratio greatly affects your ability to lose weight .

Because women generally have a higher fat to muscle ratio than men, they have a CMA of 5 to 10% lower than that of men of the same height .

This means that women typically burn 5-10% fewer calories than men at rest. Thus, men tend to lose weight faster than women. women on an equal-calorie diet.

For example, an 8-week study including more than 2,000 participants following an 800-calorie diet found that men lost 16% more weight than women, with a relative weight loss of 11.8% in men and women. 10.3% in women ( 3 Trusted source ).

Yet, while men tended to lose weight faster than women, the study did not analyze sex-based differences in the ability to maintain weight loss .


One of the many bodily changes that occur with aging is changes in body composition - fat mass increases and muscle mass decreases.

This change, along with other factors like lower calorie needs of your major organs, contributes to a lower RMR .

In fact, adults over 70 can have RMRs 20-25% lower than younger adults .

This decrease in RMR can make weight loss more and more difficult with age .

Starting point

Your starting body mass and composition can 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 people. Ultimately, weight loss is a complex process.

The National Institutes of Health (NIH) Body Weight Planner is a helpful guide to how much you can lose based on your starting weight, age, gender, and the number of calories you take in and burn .

Although a heavier person can lose twice as much weight, a person with less weight can lose an equal percentage of their body weight (10/250 = 4% versus 5/125 = 4%).

For example, a person weighing 136 kg may lose 4.5 kg after having reduce daily intake 1,000 calories and increased physical activity for 2 weeks.

Calorie deficit

You need to create a negative calorie balance to lose weight. The magnitude of this calorie deficit affects the rate at which you lose weight.

For example, eating 500 fewer calories per day for 8 weeks is likely to result in greater weight loss than eating 200 fewer calories per day.

However, be sure not to make your excessive calorie deficit .

This would not only be unsustainable, but also expose you to nutrient deficiencies. Plus, it could cause you to lose more weight as muscle mass rather than fat mass.

The sleep

sleep has tends to be an overlooked but crucial component of weight loss .

Chronic sleep loss can significantly hamper weight loss and the rate at which you shed pounds.

A single night of sleep deprivation has been shown to increase your desire for calorie-dense, nutrient-poor foods, such as cookies, cakes, sugary drinks, and potato chips .

A 2-week study randomized participants on a low- calorie diet to sleep 5.5 or 8.5 hours each night.

Those who slept 5.5 hours lost 55% less body fat and 60% more lean mass than those who slept 8.5 hours per night .

Therefore, chronic sleep deprivation is strongly linked to type 2 diabetes, obesity, heart disease and certain cancers .

Other factors

Several other factors can affect your rate of weight loss , including:

  • Medications. Many medications, such as antidepressants and other antipsychotics, can promote weight gain or interfere with weight loss .
  • Medical conditions. Illnesses, including depression and hypothyroidism, a condition in which your thyroid gland produces too few metabolism-regulating hormones, 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 can affect weight loss .
  • Yo-yo diet. This diagram of weight loss and regain can make weight loss increasingly difficult with each attempt, due to a decrease in RMR .

Best diet for weight loss

With countless weight loss diets available - all promising impressive and fast results - it can be confusing to know which one is the best.

Yet, although the creators and proponents deem their programs superior to others, there is no "best weight loss diet" .

For example, low carbohydrate diets like keto may help you lose more weight initially, but studies show no significant difference in long-term weight loss .

What matters most is your ability to follow a healthy , calorie-restricted diet .

However, following a very low-calorie diet for long periods of time is difficult for many people and the reason most diets fail .

We therefore recommend food rebalancing .

Combine healthy eating and exercise , including both aerobic and resistance training, to maximize fat loss and prevent or minimize muscle loss .

By eliminating highly processed foods and incorporating healthier whole foods, such as vegetables, fruits, whole grains, healthy fats, and proteins, you can further support weight loss and your overall health.

Safe weight loss rates

While most people hope for rapid weight loss , it's important not to lose too much weight too quickly.

Rapid weight loss can increase your risk of gallstones, dehydration, and malnutrition .

Other side effects of rapid weight loss include :

  • Headaches
  • irritability
  • Tiredness
  • The constipation
  • hair loss
  • Menstrual irregularities
  • Muscle wasting

Although weight loss may occur more rapidly at the start of a program, experts recommend weight loss of 0.45 to 1.36 kg per week, or about 1% of your body weight .

Also keep in mind that weight loss is not a linear process. Some weeks you may lose more, while other weeks you may lose less or not at all .

So don't be discouraged if your weight loss slows down .

Use a food diary, as well as Weighing yourself regularly can help you stay on track.

Research shows that people who use self-monitoring techniques, such as logging your food intake and weight, are more successful at losing and keeping weight off than those who don't .

The essential

Weight loss occurs when you eat fewer calories than you burn.

Many factors affect your rate of weight loss , including your gender, age, starting weight, sleep, and the extent of your calorie deficit.

Aiming to lose 0.45 to 1.36 kg per week is a safe and sustainable way to achieve your goals.

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