How can I lose weight quickly?

How to Lose Weight Fast: Why 10 Pounds in 3 Days Is a Myth

No, losing 10 pounds of actual body fat in 3 days is not physiologically possible for anyone eating and drinking normally. One pound of fat stores about 3,500 kcal of energy, a figure derived from body composition research such as Hall's 2008 analysis of energy balance and weight change. Losing 10 pounds of pure fat in 3 days would mean burning roughly 35,000 kcal beyond intake in that window, or an average daily deficit near 11,600 kcal. No combination of exercise and calorie restriction produces a deficit that large; even elite endurance athletes rarely exceed 4,000 to 6,000 kcal burned in a single day, and that is offset by eating.

What actually moves the scale that fast is water, not fat. Every gram of glycogen, the stored form of carbohydrate in muscle and liver, is bound to roughly 3 to 4 grams of water, a ratio documented in classic exercise physiology work like Olsson and Saltin's studies on glycogen and body water. Cutting carbohydrates hard, as many crash diets do, depletes glycogen stores and releases that bound water through urine and sweat. Add reduced gut content from eating less food and less fiber, and a 5 to 8 pound drop in 3 days becomes arithmetically possible, just not from fat.

That weight returns almost as quickly as it left. Within a day or two of resuming normal carbohydrate intake, glycogen stores refill, water rebinds, and the scale climbs back toward the starting point, which is why these methods feel dramatic but change nothing about actual fat mass.

How to Lose Weight Fast: What's the Real Timeline for 20 Pounds or 10 Kg?

Losing 20 pounds safely takes about 10 to 20 weeks, and losing 10 kg in 2 weeks is not achievable without extreme, medically risky restriction that produces mostly water loss rather than fat loss. The math changes depending on which rate applies: the general safe-rate guidance of 1 to 2 pounds a week endorsed by the CDC, or the faster 3 to 5 pounds a week seen only under medical supervision on a very low-calorie diet.

The table below applies both rates to the three targets people search for most: 10 pounds, 20 pounds, and 10 kilograms (about 22 pounds).

Even the fastest medically supervised column puts 10 kg at just under a month and a half, never 2 weeks. A 2-week timeline for 10 kg would require sustaining a deficit far beyond what an 800 kcal VLCD produces, which is why that specific search intent has no safe or legitimate answer, only a water-weight and dehydration workaround that reverses within days.

Do Weight Loss Pills Help You Lose Weight Fast?

Weight loss pills can accelerate fat loss beyond diet alone, but the effect shows up over weeks and months, not days, and the size of the effect varies enormously by drug class. None of them turn a slow diet into a 3-day miracle; they shift the ceiling on how much total weight you can lose over a year.

Orlistat (sold over the counter as Alli and by prescription at a higher dose as Xenical) blocks about a third of dietary fat absorption. Clinical data reviewed in the StatPearls orlistat monograph put typical loss at 5 to 10 percent of body weight over 6 to 12 months when paired with a reduced-calorie diet, meaning a 200 lb person might lose 10 to 20 lb across nearly a year, not a week. Gastrointestinal side effects (oily stools, urgency, gas) are common enough that many users stop early.

Prescription GLP-1 and GIP drugs move faster and further. In the STEP 1 trial, weekly semaglutide produced about 15 percent body weight loss over 68 weeks. In the SURMOUNT-1 trial, tirzepatide reached close to 20 percent at the highest dose after roughly 72 weeks, with most of that loss occurring after a several-month dose titration period, not the first few weeks. Noticeable results typically take 8 to 12 weeks as the dose is increased.

Cost is a real barrier: list prices for semaglutide and tirzepatide injections run roughly $1,000 to $1,350 a month without insurance coverage, according to KFF's analysis of obesity drug coverage. Nausea, vomiting, and constipation are common, and most of the lost weight returns within a year of stopping, since these drugs treat appetite regulation rather than curing it.

What's the Quickest Safe At-Home Routine With No Equipment?

The fastest safe no-equipment routine combines daily brisk walking with a short bodyweight circuit, adding roughly a quarter to half a pound of extra weekly loss on top of whatever a calorie deficit already produces. Nothing done without equipment will out-pace a proper diet, but this stacks the two together.

Walk briskly for 30 to 45 minutes daily, landing in the 150 to 300 minutes a week range recommended in the CDC's adult physical activity guidelines. Pair that with a step count target of 8,000 to 10,000 steps a day, tracked on a phone or basic pedometer, since incidental movement outside formal exercise adds up over a week.

Three times a week, add a 20-minute AMRAP (as many rounds as possible) bodyweight circuit: 10 squats, 10 push-ups (knee push-ups are fine), 10 walking lunges per leg, and 30 seconds of mountain climbers, repeated back to back for the full 20 minutes. This raises heart rate into a moderate-to-vigorous zone without any equipment or gym access.

Realistically, this combination burns an extra 250 to 500 calories most days depending on body weight and effort, which translates to roughly 0.25 to 0.5 lb (about 100 to 250 g) of additional weekly loss beyond diet alone. That is a meaningful add-on, not a replacement for the calorie deficit that does most of the work.

Why Does Rapid Weight Loss Come Back? The Regain Numbers

Yes, most rapid weight loss returns, and the research puts a real number on it: in Mann et al.'s review of diet trials published in American Psychologist, roughly two-thirds of dieters regained more weight than they had lost within four to five years of finishing a diet, with the majority of losses reversed within the first one to two years. This is the contradiction the generic "lose weight fast" guides never name out loud: the very methods fast enough to satisfy that search (VLCDs, extreme cuts, water-weight tricks) are, by the field's own data, the least likely to stick.

The mechanism is metabolic, not a willpower failure. Rapid, severe calorie restriction triggers what researchers call adaptive thermogenesis, where resting metabolic rate drops further than body composition alone would predict, sometimes by 15 to 25% below expected levels. At the same time, levels of the hunger hormone ghrelin rise while leptin, which signals fullness, falls, producing a biological push to eat more that can persist for a year or longer after the diet ends.

This is why a slower, smaller deficit that preserves more muscle mass and doesn't provoke as sharp a hormonal rebound tends to outperform crash approaches over any timeline longer than a few months, even though it loses the head-to-head speed comparison in week one.

Electrolytes and Warning Signs When Cutting Calories Fast

Cutting calories aggressively, especially below 1,000 kcal/day, increases the risk of sodium and potassium imbalances because reduced food intake means reduced electrolyte intake alongside continued fluid loss. Adults generally need at least 1,500 to 2,300 mg of sodium and around 2,600 to 3,400 mg of potassium daily to avoid symptoms; VLCD programs typically include a fortified formula precisely to prevent this gap, which is one reason unsupervised versions of the same calorie level are riskier.

Stop the diet and seek medical care if you notice heart palpitations, fainting or near-fainting, dark or tea-colored urine, severe dizziness on standing, or muscle cramps that don't resolve with rest. These are signs of dehydration or electrolyte imbalance, not normal "diet fatigue," and they show up disproportionately in the first one to two weeks of an aggressive cut.

The Safe-Rate Consensus: 1-2 Pounds a Week

Every method in this article gets measured against the same floor: 1 to 2 lb (0.5 to 1 kg) a week. This is the rate the CDC and the NHS both point to as sustainable for most adults, because it lines up with a moderate 500 to 1,000 kcal daily deficit rather than the extreme shortfalls that force the body to burn muscle and water alongside fat.

Pills, VLCDs, and fasting protocols can beat this pace, but they do it by trading some combination of medical supervision, side effects, or long-term durability. Anything faster should be judged against this baseline, not instead of it.