Peak Week Bodybuilding: What Changes in the Final Week

What the research shows

Not much. The Escalante review found "a dearth of evidence" behind common peak week practices, and a 2024 review by Homer, Cross and Helms, in Sports Medicine - Open, found carbohydrate strategies widespread "despite a paucity of experimental evidence". The studies are small:

• Carbohydrate loading made arms measure bigger, and upset stomachs. De Moraes and colleagues (2019, Journal of Sports Science and Medicine) measured 24 male bodybuilders after three days of low carbohydrate. The 15 who then loaded in the 24 hours before the show, at about 9 g per kg of body weight (about 4 g per lb), had thicker arm muscles on ultrasound and scored better when their silhouettes were rated from photos; in the 9 who did not load, muscle thickness did not change. But constipation was common in both groups, and 7 of the 15 who loaded had diarrhoea. The groups were based on what competitors chose to do, not assigned at random.
• Experienced natural bodybuilders gave up water and salt tricks. Mitchell and colleagues (2017, Sports) interviewed seven natural male bodybuilders with about 10 years' experience on average. All seven described loading then cutting water, and it had not worked well enough to keep doing. The three who had tried salt tricks found them inconsistent and stopped. Six used a simpler approach: easing off training and adding carbohydrate.
• One natural pro, measured through his peak week. In a case study (Barakat and colleagues, 2022, Sports), a natural professional bodybuilder cut and then raised his carbohydrate while keeping his water intake high. From three days out to show day, his muscles measured about 3% thicker on ultrasound and the layer under his skin about 10% thinner, without significant dehydration. But he was one person, and also the lead researcher.

Carbohydrate: the one lever with some support

• Cutting carbohydrate right down first may not be needed. The Escalante review favours a short cut early in the week before loading, adjusted to the person and how they dieted in prep. Homer's later review concludes that depleting glycogen before loading "may be unnecessary".
• The right amount varies widely. Homer's review suggests that loading with anywhere from 3 to 12 g of carbohydrate per kg of body weight (about 1.4 to 5.4 g per lb) may increase muscle size. For an 80 kg (176 lb) competitor, that spans 240 g to 960 g. A range that wide is why you rehearse.
• Eat foods you know. Homer's review favours quick-digesting, low-fibre carbohydrate. Escalante's favours starchy carbohydrate and advises against trying new foods in peak week.

Water and salt: why big cuts can backfire

The theory is that cutting water or salt pulls water from under the skin and leaves you "dry". There is little evidence for it, and some reasons for caution:

• Dehydration can shrink muscle. Homer's review notes that muscle water falls when you dehydrate, which may make muscles smaller, and that restricting water and salt may reduce muscle size and vascularity (how visible your veins are). Overdrinking may also leave you holding water that blurs definition.
• Salt helps carbohydrate get in. Your gut needs sodium to absorb glucose, so the Escalante review advises against cutting salt while loading carbohydrate.
• Too much water is risky too. Chappell and Simper note that hyponatraemia (low blood sodium, which can be dangerous) has been seen in natural athletes drinking too much water without added electrolytes.

The Escalante review does describe loading then cutting water, but that evidence comes from combat athletes losing body water, not from bodybuilders on stage. The simpler option it offers is keeping water fairly constant, cutting back only in the few hours before stage to avoid a swollen stomach, which "might be the best approach" if you have not done a practice run. On water and salt, "leaving these variables alone may be a better option for some competitors". If you have a heart, kidney or blood pressure condition, speak to your doctor before changing either.

Diuretics: banned and dangerous

This section is education only. Diuretics are drugs that make the kidneys pass more water, which is why some competitors misuse them.

• They are banned. As of October 2026, diuretics are on the World Anti-Doping Agency's Prohibited List, in and out of competition. The Escalante review notes they are banned for their health dangers and because they can hide other drug use. Tested federations ban them too: the WNBF bans prescription diuretics used for bodybuilding for three months before its shows, even when a doctor prescribed them, with exemptions possible for heart conditions.
• They have put competitors in hospital. These are single case reports, but serious ones. Mayr and colleagues (2012, American Journal of Emergency Medicine) describe a 26-year-old professional who took a diuretic for the first time before a show and, the day after the show, woke unable to move his arms or legs, with dangerously low blood potassium. Sturmi and Rutecki (1995, The Physician and Sportsmedicine) describe a 27-year-old professional who combined diuretics, potassium supplements and diet restriction, and was found to have life-threatening high potassium and changes on his heart tracing. They noted his case resembled that of another professional bodybuilder who died after similar practices.

If you take a diuretic your doctor prescribed for a medical condition, do not stop or change it yourself: speak to your doctor, and check your federation's rules on medical exemptions.

Training and cardio in peak week

The Escalante review uses early-week sessions to run down glycogen across the whole body, then gives muscles time to fill without fresh damage:

• Train every major muscle group early in the week, spread over three to four days, legs first, so they have the longest to recover.
• Higher reps, short of failure. Use more than 12 reps a set, stop short of failure, and taper volume and intensity.
• No new exercises, and go easy on ones that load a stretched muscle hard, such as Romanian deadlifts and dumbbell flyes, which cause more damage.
• Taper cardio, ideally dropping it before you start adding carbohydrate.

Fibre, food and digestion

Bloating can spoil a good peak. Escalante's review reports that bodybuilders in one study cut their fibre sharply, mainly by dropping fibrous vegetables, and suggests limiting high-FODMAP foods (carbohydrates that cause gas in some people) and sticking with the foods you ate during prep. On show day, Chappell and Simper found the most common strategy was eating quick-digesting, high-glycaemic carbohydrate.

The case for a conservative, rehearsed peak

The Escalante review recommends a practice run of your peak week about 2 to 4 weeks before the show, and notes that the bodybuilders in the Mitchell study had likely never rehearsed the water and salt strategies they abandoned. Homer's review suggests testing carbohydrate amounts well in advance, once you are already very lean, and changing "as few variables as possible".

A conservative peak, drawn from those reviews rather than any tested protocol:

1. Keep water and salt about the same as during prep.
2. Lower your training volume, train early in the week and taper cardio.
3. Raise carbohydrate over the last two to three days, using foods you know, and trim fibre a little.
4. Take photos every morning in the same light and poses, and adjust a little, not a lot. See how to take progress photos.
5. Write down what you did and how you looked, so the show repeats the rehearsal.

Expect the scale to move as carbohydrate and water change; judge by the mirror and photos. See how to read the scale.

Why being lean enough matters most

Conditioning, meaning how little body fat you carry, is one of the things judges score. Homer's review advises reaching stage condition three to four weeks out, then raising carbohydrate slowly, which leaves time to adjust to how your physique responds.

If you reach peak week behind, compete in the condition you have or choose a later show; do not reach for harder tricks. The dieting that gets you lean is covered in contest prep: what the weeks before a show look like.

Where coaching helps

No coach can promise a placing. What coaching can do is help you arrive at peak week lean enough, with a plan you have already tried.

With one-to-one contest prep coaching from CoachAk, your training program and daily calorie, macro and step targets are written for you in the app. Each week you send a check-in covering your weight, training and nutrition adherence, steps, sleep, energy, hunger, stress and digestion, with optional progress photos (front, side and back, relaxed and flexed). Your coach replies with written feedback and adjusts the plan, so a practice peak can be planned weeks ahead and the real one shaped by what you learned. Photos from different weeks sit side by side, and you can message your coach directly, with photos, during show week.

If you are planning a show, read more about contest prep coaching or apply for coaching.