You're better off starting a diet and fitness program slowly and carefully.
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Three weeks does not represent a lot of time for you to lose weight, and it's definitely not enough time for you to develop new, healthy eating habits that can last a lifetime. But if you absolutely need to shed pounds in 21 days -- maybe for a once-in-a-lifetime special event -- you do have some strategies you can use to help you get slimmer in time. The amount of weight you ultimately lose will depend on which strategy you choose.
Medically Supervised Diets
If you have a medical reason that explains your urgent weight-loss needs, you may be eligible to enroll in a medically supervised diet program, according to the University of Texas-Southwestern Medical Center. These programs, generally run by universities or major medical centers, generally use liquid diets that consist of about 800 calories each day. They also include counseling aimed at helping you change your lifestyle to address the reasons you're overweight in the first place. If your body normally burns about 2,000 to 2,500 calories each day, you can lose up to 10 lbs. in 21 days on this type of diet.
Low-carbohydrate diets work well initially to help you lose weight fast -- in fact, you tend to drop pounds more quickly on a low-carb eating program than you do on a low-fat type of diet, according to the University of Maryland Medical Center. In the first phase of the popular Atkins diet program, for example, participants can eat no more than 20 g of carbs each day -- and it's fairly common to see weight loss of 5 lbs. a week in people following the diet carefully. Therefore, if you follow this type of low-carb diet for 21 days, you potentially can lose up to 15 lbs. Be careful, though, since researchers haven't finished evaluating the long-term effects of very low-carb diets.
Simple diet changes -- substituting carrot sticks for potato chips -- can have a surprisingly quick effect on your weight, as can instituting a new exercise program, according to Columbia University. Although you're unlikely to see Atkins-style weight-loss results of 15 lbs. in 21 days if you just start eating healthier and exercising, you will see some results -- and you'll be able to sustain those results more easily. If you carve 400 calories a day out of your normal diet and burn another 400 calories each day through your new fitness routine, you'll lose about 5 lbs. in three weeks.
You're actually better off to start a diet and fitness program slowly and carefully than to jump in with both feet, according to Columbia University. You risk fewer injuries that way and also reduce your chances of burning out on the program before you see real results. It's possible to lose up to 15 lbs. in 21 days, but you're more likely to keep the weight off if you only lose about 5 lbs. Regardless of which weight-loss method you choose, discuss your plans and your current state of health with your physician before beginning any program.
FAQs
in 21 days if you just start eating healthier and exercising, you will see some results -- and you'll be able to sustain those results more easily. If you carve 400 calories a day out of your normal diet and burn another 400 calories each day through your new fitness routine, you'll lose about 5 lbs.
What is the maximum weight you can lose in 21 days? ›
To lose weight and keep it off, it is better to follow a sustainable healthy dietary approach with regular exercise. According to the 21-Day Fix, people can lose up to 15 lbs in 21 days.
How much weight can I lose on a 21 day fast? ›
Fasting is the easiest way to lose weight. One may lose anything from 8 – 12 kg during a 21-day fast. But you will gain back most of this weight once you return to normal food. Following a controlled diet after the fast can help in maintaining the reduced weight.
How much weight can you realistically lose in 20 days? ›
You can safely lose 3 to 6 pounds in 20 days by making changes in your diet and physical activity. According to the Weight-control Information Network, incorporating healthy habits into your daily life not only increases the chance of weight loss, but will help you keep the lost pounds off.
How much weight can I realistically lose in 24 days? ›
That answer depends on the individual. Someone with a larger body can typically lose more because they have more weight to begin with. "In general, 1 to 2 pounds per week, or 4 to 8 pounds per month, is a safe and sustainable amount to lose," says Sarah Gold Anzlovar, M.S., RDN, LDN and founder of Sarah Gold Nutrition.
Can I lose 10 pounds in 20 days? ›
Steady weight loss is considered 1–2 pounds a week, so losing 10 pounds may take 5–10 weeks or more. However, weight loss is not always consistent and people's experiences differ. Losing weight too fast may be unsafe.
Can you lose 15 pounds in 21 days? ›
The 21 Day Fix is a diet and exercise plan that can help you lost up to 15 pounds in three weeks. It supports healthy eating and encourages exercise, but it may be too restrictive of a diet for some. Though slow, consistent weight loss is healthiest, it's not uncommon for people to want to shed pounds quickly.
What happens if you only drink water for 21 days? ›
In fact, several studies have linked water fasting with some impressive health benefits, including a lower risk of certain cancers, heart disease, and diabetes. Water fasting may also promote autophagy , a process in which your body breaks down and recycles old, potentially dangerous parts of your cells.
How do I lose weight rapidly within 21 days? ›
A: The 21-day diet plan for weight loss works by creating a calorie deficit. It means consuming fewer calories than you burn through physical activity and body functions. Consuming nutrient-dense foods high in fibre, protein, and healthy fats can keep you full and promote weight loss.
What happens to your body when you water fast for 21 days? ›
Some health benefits of water fasting are detoxification, improved digestion, and enhanced mental clarity. Some studies suggest it may aid in weight loss and insulin sensitivity.”
Summary: It's unrealistic and dangerous to attempt a 20-pound weight loss in 2 weeks. Doing so would require a deficit of 5,000 calories per day, which is far more than what most people eat and burn in a day.
Can I lose noticeable weight in 2 weeks? ›
Setting realistic and healthy weight loss goals is crucial for long-term success. According to the Centers for Disease Control and Prevention (CDC), a safe and achievable weight loss goal is to lose 1 to 2 pounds per week. This means that in two weeks, you can safely lose between 2 to 4 pounds.
Can you lose noticeable weight in 3 weeks? ›
You can start seeing differences in yourself as early as two weeks with rapid weight loss. However, most people will notice a significant difference in themselves anywhere between four to eight weeks, Guzman said.
What is the maximum weight loss in 21 days? ›
How many kgs can I lose in 21 days? - Quora. Realistically and safely you can drop a couple of kilos if you diet and exercise. You can even drop 4 kilos if you go for some fancy dieting techniques like keto or intermittent fasting.
What is the maximum weight someone can lose in a week? ›
The best and safest way to lose weight is to do it gradually. When people lose lots of weight quickly, they tend to be losing the wrong kind of weight – muscle, water, and bone mass – rather than losing fat. The Academy of Nutrition and Dietetics recommends trying to limit weight loss to one or two pounds per week.
How many pounds do you lose when you don't eat for 24 hours? ›
Changes in weight after fasting for 24 hours
The day after the fast, you will see the number drop significantly—anywhere from 1.5 to 3 pounds. [6] While much of this is water weight, you still lose fat. [7] After a few days, you'll gain weight as you hydrate yourself. But this doesn't mean you haven't shed any pounds.
What is the maximum possible weight loss in 2 weeks? ›
A realistic and healthy weight loss goal is to lose one to two pounds per week. To lose weight in a healthy manner, you should cut 500 to 1,000 calories a day by eating less and exercising more. Anything more than that may cause harmful effects to the body, including stress and tiredness.
Can you lose 20 pounds in 20 days? ›
Summary: It's unrealistic and dangerous to attempt a 20-pound weight loss in 2 weeks. Doing so would require a deficit of 5,000 calories per day, which is far more than what most people eat and burn in a day.
Can I lose 20 lbs in 27 days? ›
“A 20-pound weight loss [goal within one month] would require a person to eat around 2,300 fewer calories than they burn every single day. This [deficit] would be pretty difficult [to achieve] unless their daily metabolic rate is considerably higher than 2,300 calories,” she explains.
How can I lose my maximum weight in 20 days? ›
How to naturally lose weight fast
- Intermittent fasting.
- Tracking diet and exercise.
- Mindful eating.
- Protein with meals.
- Avoid sugar.
- Fiber.
- Gut bacteria balance.
- Sleep.
