FOR years boxers have been using a whole manner of weird and wonderful techniques for cutting weight. For some the drastic weight loss is worth the competitive advantage they gain, stepping into the ring bigger and stronger than their opponent. For others, famously Floyd Mayweather, fighting at close to your natural weight offers a distinct advantage both in terms of speed and stamina. Obviously each approach has its merits, but objectively speaking what are the pros and cons to each protocol? Here Ross Edgley investigates and addresses how carbohydrate and water manipulation can help your weight cut but possibly impact sports performance.

Water & Hydration: Good for Weight Cutting

Perhaps the most widely used method for cutting weight is through water manipulation. This is because between 50%-75% of the human body is water so by using diuretics, saunas, sweat-suits and restricting water intake you can dramatically impact your overall weight. But it’s important to note that cutting too much weight through water depletion can dangerously affect your organs and even result in death, plus some sports scientists argue the resulting decline in performance isn’t worth the perceived size and strength advantage gained.

Water & Hydration: Bad for Weight Cutting

This is because research published in the sports journal entitled, “Sport nutrition: an introduction to energy production and performance” set out to quantify the degree to which dehydration affected performance and claimed becoming dehydrated by as much as 5% can lead to a reduced physical capacity of up to 30%. To put that into perspective with a sporting example, London 2012’s Olympic marathon winner Stephen Kiprotich won in a time of two hours, eight minutes and one second according to But based on the above premise, if he was dehydrated by five percent, in theory, he would have finished in a time of around 2:46:00 and placed 84th out of the 85 who finished the race. So, put simply if you are going to cut weight through water manipulation, which is effective, be sure to have a rehydration plan in place immediately following the weigh-in or suffer the consequences of impaired performance.

Carbohydrate Depletion: Good for Weight Cutting

Carbohydrates are your body’s primary fuel supply. They come in the form of potatoes, rice, bread and certain sports drinks and they’re stored in the body as muscle glycogen to be used during any form of physical activity. Unfortunately for every kilo of muscle we store 18g of muscle glycogen. Therefore it stands to reason by restricting your body’s primary fuel supply you can significantly affect the number on the scales.

Carbohydrate Depletion: Bad for Weight Cutting

But many sports nutritionists would argue cutting your body’s main source of energy just to make weight is wrong and is like committing ‘sporting suicide’. This is because a study conducted in Stockholm, Sweden studied an athlete’s ability to exercise when they were depleted of carbohydrates. They found they fatigued and ‘gassed out’ about 40% quicker than those who were on a high carbohydrate diet. This means that although you can lose a certain amount of weight through a low carbohydrate diet, if you’re not able to load the body back up with carbohydrates (i.e. replenish muscle glycogen stores) between the weigh-in and the fight, you could be working at only 60% of your maximum ability.

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