Friday, September 19, 2008

Low carb diets?

Hi again everyone

As you all know, I recommend a diet that consists mostly of non processed foods such as fruit, vegetables, eggs, meats and fish. I read an interesting article which talks about this and low carb diets I have included below.

Please note that I do not necessarily recommend a low carb diet. Of course a diet that does not include a lot of bread, pasta, rice etc will be lower in carbs naturally. Fruits and vegies contain lots of carbs too though, but they also have loads of water and fibre which makes them extremely hard to consume too many calories with.

www.ThePaleoDiet.com
Loren Cordain, Ph.D.
Issue: # 2008 - 10 / September 19, 2008


Hello! Welcome to The Paleo Diet Update, your guide to eating for optimum health. The Paleo Diet is based on the simple concept that the healthiest diet is one which attempts to mimic the diet that we evolved to eat.

Until the invention of agriculture a mere 333 generations ago, humans rarely had access to high amounts of carbohydrate containing foods. When farming replaced the hunter-gather lifestyle, the macronutrient content of the human diet changed dramatically. Today most people consume bread, rice, pasta, sugar, and other high carbohydrate foods with virtually every meal. Others have heard the message about the benefits of reducing carbohydrates, but may go too far too quickly.



People who go on a low-carb diet will sometimes report feeling weak or light headed during the first few days on their new eating pattern.

Whether this happens depends on two main factors: 1) the total carbohydrate restriction and, 2) the total caloric restriction.

Popular low carb diets typically restrict carb calories to 50 grams (~200 kcal) or 100 grams (~400 kcal). If the diet is low in calories and carbs are restricted to less than 100 grams, many people will feel weakness because their muscle and liver glycogen stores will become depleted and they must rely upon beta oxidation (the metabolism of triglyceride) as their primary substrate source.

Additionally, the brain can only use glucose as an energy source, hence hepatic gluconeogenesis (the synthesis of glucose from either protein or fat in the liver) represents the primary glucose source. However, gluconeogenesis is inefficient and can only supply small quantities of glucose.

All of these metabolic adaptations - beta oxidation, hepatic gluconeogenesis and ketosis (a by product of carbohydrate restriction and beta oxidation) - upset homeostatic mechanisms shaped by a lifetime of high carb intakes for the average Westerner.

With the Paleo Diet, we advise people to get all of their carbohydrates from fruits and vegetables and to restrict grains, sugars, legumes and processed foods. Carbohydrates are not restricted on the Paleo Diet, but because fruits and vegetables contain so much fiber and water, it is difficult to consume more than about 30 percent of the daily energy from these foods.

Most people don't experience weakness or lethargy upon adoption of the Paleo Diet, but rather the opposite. Their energy levels remain stable over the course of the day.


I think that he has hit the nail on the head here. Low carb diets do usually work in the short term, but are very hard to maintain and have their own set of side effects.

Sometimes we do need loads more carbs than this type of diet can supply however. For instance I am presently training really hard and long for a half ironman distance traithlon in a couple of months. I use carbohydrate sports drinks while training and sometimes afterwards for recovery. I need to do this as I am using very high intensity training usually twice a day for up to 14 hours per week.

The average person will not need to supplement their diet with extra carbs if they are consuming lots of fruits and vegetables. Fruits and vegetables also have many other health benefits such as fibre, vitamins, minerals and phytochemicals that are vital to our healthy existence.

So heap up those plates and get training.

Jo

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