I usually do not do this but this time I will make an exception. Instead of wrtting a blog, I am going put a link to a video that talks about nutrition and diet from a scientific point of view. It is only 15 minutes long and it is explained in a simple manner. In my opinion one of the best videos I have seen. Hopefully you guys like it and learn something from it.
https://www.youtube.com/watch?v=fqhYBTg73fw . If the link gets blocked, all you have to do is go to youtube and look for Doctor Mike Evans.
You probably have heard of this expression before if you are a runner and may have even experienced it yourself. ¨Hitting the wall¨ usually happens around the 29th to 35th kilometer. The runner´s pace slows down considerably, the legs become very heavy and thinking often becomes hard and confused (now that I think about it, this last thing happens to me quite often). This happens because we basically run out of available energy.
The runner´s primary sources of energy during prolonged exercise are carbohydrates and fats. We have lots of stores of fat, around 70.000 to 75.000 kcla, even in a lean adult, but the fat metabolism requires a constant supply of oxygen, and delivery of energy is slower than that provided by the carbohydrate metabolism. The carbs reserves (glycogen), on the other hand, are quite limited and have only around 2.000 to 2.400 kcla, which happens to be enough energy to get us to kilometer 29-30. Since the body is much less efficient at converting fat to energy, running pace slows and the runner suffers from fatigue.To make things even worse the brain, which only accounts for 2% of your weight and consumes 20% of your energy, gets its fuel source only from carbohydrates!! So now next you ¨hit the wall¨you will know why that is. Hope you liked it. Till next time
Kenney L, Wilmore J, Costill D. Physiology of Sport and Exercise sixth edition, Human Kinetics,2015.
I´m a big fan of carbs and I usually eat quite a lot of them. From bread to pasta, to rice, I love them. Although lately they have been getting a bad rap and most people when losing weight are trying to take them out. Even though different studies have shown that the most important factor in these types of diets is the percentage of proteins you eat. In other words, it really doesn´t matter if you go on a low fat diet or a low carb diet, both of them will be more or less effective if you keep your protein intake high (1-3). But anyway, let´s try to explain carbs in simple way.
Carbs are your body´s preferred and most efficient energy source for intense training. Carbs can be stored in the muscle and in the liver as glycogen. Carbs can be divided into two groups more or less, SIMPLE CARBS AND COMPLEX CARBS:
- Simple Carbs: consists of a single sugar molecule (monosaccharide) or two molecules linked together (disaccharide)
- Monosaccharides: Include fructose, glucose and galactose.
- Disaccharide: Which is formed by a combination of two monosaccharide molecules. So for example sucrose (which is table sugar) is formed by the combination of fructose and glucose. And lactose (dairy sugar) is composed of lactose and glucose.
*Simple Carbs are digested quickly and cause a rapid rise in blood sugar, but they also cause a rapid fall after. Meaning you eat these and after a while you are again hungry! That is why you should be careful with simple carbs, especially if they are not natural. Now this doesn´t mean you shouldn´t be eating fruits. Fruits have a lot of fiber and this cause that the rise in blood sugar to go more slowly and on top of that fruits have a lot of phytochemicals (lots of healthy things ;).
- Complex Carbs: Also know as polysaccharides. Most complex carbs contain fibre and they provide sustained energy without the highs and lows you get after eating simple carbs. You can divide the complex carbs into two groups.
- Starchy Carbs : Which include potatoes, yams, oats, beans, brown rice, lentils, green peas, corn, pumpkin, whole wheat.
- Fibrous Carbs: Which include broccoli, spinach, asparagus, cucumber, tomatoes, cauliflower, brussels sprouts, onions, peppers, mushroom, aubergine, lettuce .
We should try to eat more fibrous carbs because of the fibre. Like I said before, fibrous foods take more time to chew and swallow and they have a low calorie density!!
So to summarize, carbs are not that bad and we SHOULD be eating them. The only thing to watch out for is make sure these carbs are ¨NATURAL¨ and not processed, and when eating carbs remember the word ¨dark¨, meaning, you should be eating ¨dark¨ bread, ¨dark¨ pasta and ¨dark¨ rice. And if you want to lose weight try to switch from starchy carbs to fibrous carbs!!
Hoped you enjoyed it!!
- Hu T, Mills K, Demanelis K, Eloustaz M, Yancy W, Kelly N T, He J, Bazzano L. Effects of Low carbohydrated diets versys Low-Fat Diets on Metabolic Risk Factors: A Meta-Analysis of Randomized Controlled Clinical Trials. Am J Epidemiol. 2012 October 1; 176: S44-S54
- Loria-Kohen V, Gomez-Candela C, Fernández-Fernández C, Pérez-Torres A, Garcia-Puig J, Bermejo LM. Evaluation of uselfulness of a low calorie diet with or without bread in the treatment of overweight /obesity. Clin Nutr.2012 Aug;31 (4): 455-61.
- Soenen S, Bonomi AG, Lemmens SG, Scholte J, Thisjssen MA, van Berkum F, Westerterp-Plantenga MS. Relatively high-protein or ¨low-carb¨energy-restricted diets for body weight loss and body weight maintenance. Physiol Behav 2012 Oct 10;107(3):374-80.