Questions like this are asked all the time - i.e., what carbs to eat - so I'm going to try to make this as comprehensive as possible as I have nothing to do at work today.
There are many factors to consider when determining your carb choices: GI, complex v simple carbohydrate, nutrition density, antioxidants, satiety.
Hopefully below is some guidance on this.
GI:
GI is a measure of how quickly carbs are converted into glucose. Many argue that low GI foods are generally preferable, except PWO, where high GI foods are preferable. The theory is that low GI foods provide a slower release of energy, increasing satiety and providing more stable insulin levels facilitating fat burning. On this view, high GI foods provide “spikes” of energy and spike insulin levels, negating fat burning.
What are "good" carbs in terms of GI:
- the lowest are legumes (e.g., kidney 28), pearl barley (25).
- Sweet potatoes and old-fashioned/steel cut Oatsbrown rice are however the most popular, and are also quite low, 50's.
- Green peas, often overlooked, are also low (48). Other options include corn (low/medium), wheat (medium) etc.
- fruit can be quite low (grapefruit, apples) to high (watermelon)
- milk is very low GI (milk is mainly a carb source), but has a high insulin index
See generally
http://www.carbs-information.com/glycemic-index/porridge-oats-gi-value.htm
What are high GI carbs that may be useful PWO if you want real foods:
High GI foods generally promote greater insulin responses and therefore may be more anabolic PWO. Most high GI foods are quite processed and provide little nutrition however (white rice, bread etc). However, nutritious high GI foods do exist (white potato, pumpkin).
CRITICISMS of GI:
When fat and protein are added to a meal, the GI of the meal is lowered. GI values are measured in a fasted state where carbohydrates are consumed alone – not something we would do often.
Moreover, GI doesn’t always correlate well with nutritional density or satiety.
Pumpkin for example is high GI, but is quite possibly the most nutritious starchy carb. Moreover, Pumpkin and white potato have high GI’s but also high levels of satiety.
SO WHAT ELSE SHOULD YOU CONSIDER:
Complex carbohydrates v Simple Carbohydrates (sugars):
Carbohydrates can be either stored by your body as liver or muscle glycogen, or if these storage facilities are full, converted into at fat. More glycogen can be stored in the muscles than the liver. Muscle glycogen is chiefly use to fuel workouts; liver glycogen is chiefly use to fuel bodily functions, e.g., your brain.
The term complex carbohydrate is somewhat misleading but still useful. Simply because something is chemically classified a complex carb, does not mean it is slow digesting, e.g., maltodextrin, white potato.
However, the terms complex carb is still very useful because all complex carbs can be completely broken down into glucose by your body, and therefore the carbs can be stored in your muscle as glycogen. Simple carbs (sugars) cannot necessarily be stored as muscle glycogen.
The 2 advantages of this is that complex carbs are therefore:
- They are less fattening, because your muscle stores of glycogen > liver stores
- are more useful whilst exercising in a sub-calorie state, where your body is likely to be carb depleted and lacking energy in any event.
The most important simple carbohydrates are glucose, fructose, sucrose (1/2 glucose, 1/2 fructose) and lactose (1/2 glucose, 1/2 galactase), as well as HFCS, which has no place in a cutting diet and will be therefore ignored.
Glucose can be stored as muscle glycogen, and therefore frequently is used in post workout shakes. Fructose however can only be stored as liver glycogen. Therefore, fructose, sucrose are considered more likely to be converted into fat than complex carbs. It seems that no one has a definitive answer as to whether galactase can be stored as muscle glycogen, or merely stored as the liver. Therefore, precisely how fattening milk sugars are is unclear, although milk does have a high insulin index.
PRACTICAL APPLICATIONS of this DISTINCTION:
The carb sources that have the highest % of complex carbs and least level of fructose/galactase are in rough order:
(1) grains, rice, white potatoes, yams, and legumes have generally no sugar
(2) sweet potatoes, pumpkin, and to a lesser extent green peas also have reasonably strong complex carb to sugar ratios.
(3) Fruits and milk are almost exclusively sugar carbs (fruit sugar is mainly fructose, but also includes glucose/sucrose; milk sugar is lactose).
It should also be noted that most fibrous green veggies, whilst containing few net carbs, principally contain sugar as their net carbs.
See nutritiondata.com for more specific information.
Given that most people say the liver's capacity to process fructose is 50 grams per day, this means fruit should be consumed in moderation whilst cutting. A medium size apple for e.g., contains the equivalent of 13 grams of fructose.
So how much fruit should you eat per day?
There is no clear answer. You need to consider how many vegetables you are eating per day. For example, if you were to eat 1kg of veggies per day consisting of brocolli, cauli, cabbage, red peppers, spinach equally, that still gives you 24 grams of sugar, fructose being the main contributor. Alternatively, 300 grams of sweet potato would give you 19 grams of sugar.
Finally, some argue that some fructose is helpful whilst cutting, because depleted liver glycogen may place the body in a catabolic state (OMEGA for one has argued this I believe).
Others argue no fructose should be a cutting diet (see abcbodybuilding.com) because it minimizes energy levels in a gym.
Another useful consequence of the simple v complex carb distinction is the need to minimize sucrose and fructose PWO, because these sugars do not replenish muscle glycogen. Whilst some sucrose and fructose may not be hurtful, it will not replenish muscle glycogen to the same extent as complex carbs or glucose (hence, why maltodextrin, dextrose, waxy maize are popular PWO carb choices). White potato would appear to be the best real food choice (high GI, moderate levels of nutrition, and if Russet potatoes are chosen, high antioxidant levels).
NUTRITION DENSITY
Some carbs are more nutritious than others in terms of minerals/vitamins per calorie.
Nutritiondata.com provides a useful assessment of this (although I keep mentioning the site, I'm not affiliated with it and it is free in any event).
Generally speaking, of carb sources, the following provides a rough ranking of nutritional density for carb sources (other than fibrous vegetables). It is very rough, and you should consult a database to see precisely whether the vitamins and minerals you require are found in the food:
(1) Green peas, Pumpkin
(2) Sweet Potatoes, Legumes
(3) Oats, Barley, White Potato, fruits (note fruits vary considerably though, from berries, apricots being quite nutrition dense, to apples for example being far less so)
(4) Brown Rice, Most grains, corn
(5) Processed cereals, bread
(6) Sugar
Providing the food is natural (i.e., 1-4), i.e., not man made or processed, generally speaking the carb will provide a reasonable level of nutrition.
Note, brans (e.g., wheat bran, oat bran) have greater nutritional density than the whole grain, although it is argued that that the bran interferes with the absorption of other nutrients. Brans such as oat bran, containing high levels of soluble fibre, may be particularly useful in combating cholesterol issues.
ANTIOXIDANTS
Another thing to consider is the level of antioxidants the carb sources have. How important antioxidants are is unclear and currently debated. Some studies have shown that high dosages of antioxidants actually interfere with your bodies ability to produce them and are counter productive.
A widely used measure of antioxidants is the ORAC score. Based on this measure, the best carbs include (
http://en.wikipedia.org/wiki/Oxygen_Radical_Absorbance_Capacity)
- certain legume varieties, e.g., lima, and small red beans.
- berries, apples, and plums
- russet potatoes (although white potatoes are very low).
SATIETY
Lastly, for many people, hunger is a real issue whilst cutting, and therefore foods that satisfy hunger more are likely to be of most benefit (satiety).
Satiety is not necessarily correlated with GI, with potatoes and pumpkin being clear example.
Many factors could be relevant here in determine satiety, and what one person finds satisfying may not be another. Consider in selecting your foods
- GI;
- fibre content, particularly soluble fibre
- calorific density, e.g., 1kg of pumpkin has the same many calories as 250 grams of potatoes, or 500 mls of coke, and is therefore more filling. Similarly, for this reason oat bran is more filling than oat meal IMO.
- is the food natural, or manmade (IMO, the less processed, the more filling)
Calorific density can be manipulated to some degree.
For example, eating 100 grams of oats dry is less likely to satisfy hunger than microwaved with 3 glasses of water.
In addition, combining carbs with protein (and possibly fat) increases their satiety.
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