Thursday, 9 July 2009

Nutrition 101

Too keep my brain sharp and to write about some of the stuff thats interesting me atm here is a quick post on some basic nutrition for health, enjoy.

Carbohydrate: Humans have evolved having a sweet tooth (The history and evolution of the human diet is something I'm currently fixated with lol) and will often crave carbohydrates in their diet. While our ancestors would have snacked on fruits rich in natural sugars, the refinement and creation of simple sugar rich snacks has been linked with the increasing levels of obesity and metabolic disorders such as type 2 diabetes. The understanding that carbohydrate containing foods effect our blood sugar levels and can create cravings and mood/energy fluctuations has lead to the development and popularisation of low carbohydrate diets.

A low carbohydrate diet typically favoured by individuals who are trying to lose weight recommend consuming 20% or less total calorific intake from carbohydrates this equates to 20 to 60 g per day (to put this in perspective 30g of cheerios has around 30g of carbohydrates while a 180g baked potato has 55g)

Restricting carbohydrates is thought to facilitate weight loss as it limits the amount of glucose, the body's preferred energy source, meaning that stored fat will be used in its place, this is the same philosophy many people employ when working out in the morning on an empty stomach. I would not advice this diet to be used by any one participating in Brazilian jiujitsu for more than 3 hours a week unless they are particularly overweight (will post more on weight status next post). Instead it is wiser to obtain 50-65% of daily energy intake from whole grain carbohydrates including brown rice and pasta, pulses and beans, rye bread, 3 servings of fruit and 4 servings of vegetables while limiting the amount of processed sugar rich snacks and drinks.

If your still not convinced that low carb diets can be detrimental to training over a long time period read

Fat: Fat gets a bad reputation as 1g provides 9kcal, double that of carbohydrate and protein and so it is often linked with weight gain. However it is important to understand that there are 2 different types of fat distinguished by their differing chemical properties, known as saturated and unsaturated fat. Saturated fat is solid at room temperature and found in diary products, snacks like cakes, chocolate, crisps and pastry and the fat that can be seen on cuts of red meat. Many of us consume too much of this type of fat (high amounts in take away food, crisps chocolate full fat dairy and red meat) which can have detrimental effects on our cholesterol and lipid profile.

see for more info on the saturated fat content of foods

Unsaturated fats (Monounsaturated and polyunsaturated fats) are typically found in vegetable oils and spreads and are liquid at room temperature, these provide the essential fatty acids omega 3 and 6 that our body can not synthesis and therefore must be obtained through diet. A diet that provides the recommended amount of essential fatty acids is particularly important for anyone participating in bjj as it also helps with joint health.

The recommend intake of fat is less than 35% of total daily calories for total fat intake and less than 15% for saturated fat intake. For example if you are consuming 2000kcal a day then around 76g of fat or 684kcals. However it would be beneficial if aiming to lose weight or improve health to consume lower levels particularly of saturated fat.

Protien: Protein is used for growth and repair of the body cells, it is composed of amino acids. For a food to be a high quality or complete source of protein it must contain 9 essential amino acids in the right proportions. The recommended dietary intake of protein for is 0.8g per kilogram of body weight which can be obtained by eating by 2-3 servings of meat (or vegetarian meat alternative) daily which provide about 45 to 65 grams of protein.

Most of us training will probably be consuming higher levels of protein than this to aid in recovery and muscle growth, while this is a sensible approach as Protein ingestion before or after exercise clearly results in positive muscle anabolism (growth) it should be noted that more than 10g of protein will most likely be oxidised for energy and not used for muscle building.
For more detailed info on optimum protein intake read

So to put all that into context... The for the average person consuming 2000kcal a day a general guideline would be as follows
protein: 15-25%
carbohydrates 50-65%
fat 20-35%

Nutrition is a very individual thing and is infulenced by weight, age, gender, size, health and training status. My next nutrition post will talk more about the nutritional requirements of those of us training in bjj whether it be in the short term i.e before tonights training session, or more long term i.e. in the run up to next months competition.

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