Questions about carbs
THE FAQ FORUM IS “READ-ONLY”, SO YOU WILL NOT BE ABLE TO ADD COMMENTS TO THIS THREAD. IF YOU HAVE ANY ADDITIONAL QUESTIONS OR WOULD LIKE TO DISCUSS ANYTHING RELATED TO WHAT YOU HAVE READ HERE THEN PLEASE RETURN TO THE MAIN FORUM
When I’m talking about carbohydrates do I need to focus on the total amount consumed, or is it more important to look at the total amount of sugars?
For carbohydrate the key message we aim to provide is that it is the total amount consumed that is most important, rather than “of which are sugars”, as all carbs raise blood glucose. If the participants are happy with the AMOUNT of carbs they are having we then suggest they may want to consider the TYPE of carbs.
What does “Total carbohydrate” refer to on food labels?
Starch and sugar make up the total carbohydrate. In the UK fibre is listed separately and is not included in with the carbohydrate. Therefore, in an avocado, if the total carb is 1.9g per 100g and the sugar content is 0.5g per 100g, then starch will be 1.4g per 100g. The only exception to this is where a product contains polyols* such as xylitol. For example, No Added Sugar chocolate per 100g states something along the lines of:
Total carbohydrate 49.7g
Of which are sugars 11.1g
Of which are polyols 33.1g
This means that starch will be 5.5g (49.7g – 11.1g – 33.1g = 5.5g)
*Although these polyols are classified as carbohydrates they are not absorbed and used in the body in the same way, and they do not cause blood glucose to rise. These therefore do not need to be counted when assessing how many carbs someone is consuming
On food labels, is it true that if there is a greater difference between total carbs and sugar then it’s better for people with diabetes?
No. All foods containing carbohydrate impact on blood glucose levels and therefore the total amount of carbohydrate consumed is the key factor to consider. The building blocks of starchy foods are glucose, which directly raise blood glucose levels. Table sugar, fruit sugar and milk sugar contain some building blocks that impact on blood glucose immediately but others that get stored in the liver, having a delayed impact on blood glucose levels or getting converted to fat.
What GI rating do bagels, ciabatta and paninis have?
Bagels, ciabatta and paninis are normally made from white flour, and therefore tend to have a high GI. Adding butter or dipping in olive oil would lower the GI because fat delays the stomach emptying, but this ISN’T the best solution because the breads will still increase blood glucose and stimulate the release of insulin. It is more important to consider the amount of carbohydrate in these products and ensure that they are not being eaten to excess. Just one of any of these types of bread can have around 50g carbs, so they all provide a lot of carbohydrate. Remember, it is the AMOUNT of carbs you eat that has much more influence on your blood glucose levels and body weight than the type!
What is the best type of bread for me to eat?
Most breads contain a high amount of carbohydrate, so may need to be avoided or reduced if following a low carb or Mediterranean dietary approach. White, brown and wholemeal breads are all considered quick-releasing/high GI foods, whereas wholegrain and seeded varieties are considered medium-releasing/medium GI foods as they contain more fibre. You can also purchase low carb breads and bread mixes.
How much uncooked rice/pasta would be needed to give the cooked amounts listed as portions?
The ratio of raw to cooked pasta/rice is roughly 1:2, i.e. the weight doubles when cooked. Thus, the raw weight would be half the cooked weight.
Does the glucose from fruit, milk and sugar go to the blood stream to be used in the same way the glucose from starchy carbohydrates does?
Yes, whilst the fructose or galactose from these foods/drinks go to the liver the glucose still enters the blood stream where it can be taken to the body cells to be used for energy, or to be stored as glycogen or fat.
Why is the rate of absorption of the carbs in milk and fruit slower than starchy carbs?
The digestion of fruit is slowed down in the gut due to the soluble fibre; and the digestion of milk is slowed due to the protein and fat, which delay gastric emptying. For these reasons the carbs are absorbed more slowly. The impact on the blood glucose is also slower, and smaller, because the fructose (from the fruit) and the galactose (from the milk) have to go to the liver to be processed and so do not go directly into the blood stream.
How long does it take the body to get rid of 1tsp of sugar?
This will differ based on many factors, such as:
1. How insulin resistant the person is
2. How active they’ve been
3. What their pre-meal blood glucose value was
4. What else they ate with the sugar (e.g. other carbs? Protein? Fat?)
However, generally speaking 10g carbs (2 tsp sugar) increases blood glucose by 2-3 mmol/l. Blood glucose levels tend to peak at between 1-2 hours and should then return to normal within 3-4 hours.
Why is fibre good for me and how much do I need?
There are two main types of fibre: soluble and insoluble. Soluble fibre forms a viscous gel in the gut and slows down the absorption of glucose into the blood. Foods with soluble fibre are therefore low GI, or slow releasing, foods. Soluble fibre can be converted into short chain fatty acids in the gut and used as energy to feed our healthy gut microbiota. Insoluble fibre reabsorbs fluid in the large bowel enabling stools to be softer and easier to pass. It therefore helps to prevent and treat constipation (as long as sufficient fluid is consumed). Fruits and vegetables contain both types of fibre. The UK recommendations are for adults to consume 30g of fibre each day. This can be achieved through any dietary approach by choosing real foods in preference to processed ones.
Is it true that all carbs get digested and absorbed within 25-30 minutes and is glycaemic index now disproven?
Glycaemic index is essentially a ranking system examining how quickly a carb containing food is digested and absorbed (the higher the number the faster this happens). Factors which manipulate how fast a carb is absorbed include:
– Other nutrient contents (does it contain fat and/or protein?)
– The fibre content of that food
– The chemical breakdown of the carb (is it exclusively glucose or does it contain fructose/galactose)
These different factors will influence how quickly the carb processes through our digestive tract e.g. if you had a slice of white bread which is just glucose it will process very quickly and increase blood glucose levels in a short period of time (it is high GI) whereas if you has a glass of milk the combination of the protein, fat and galactose will slow down the digestive process meaning it will take longer for the carb to be absorbed (making it a low GI food).
Why do new potatoes have a different GI to old potatoes?
New potatoes are harvested in the spring and are therefore less mature. They contain more amylose (branched chain) starch (as opposed to amylopectin) and therefore have a medium GI. In contrast, old potatoes have more amylopectin (straight chain) starch and therefore digest and release glucose more rapidly.
How does 100g of old potato give you 15g of carbs, yet only 50g of chips gives you 15g. Why would the different weights of the same type of food (potato) give you the same amount of carbs?
The difference in the weight of the two products is down to their water content. When potatoes are cut into chips and fried they lose more water (making them more carb dense – so it requires less ‘potato’ to yield 15g of carbs, due to water loss).
Is honey classed as a natural sugar or added sugar?
Honey would be classed as a natural sugar, as the sugar occurs naturally (rather than added in during processing). However, it is also classed as a free sugar. Free sugars are defined as “all monosaccharides (glucose, fructose and galactose) and disaccharides (sucrose, maltose and lactose) added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and unsweetened fruit juices”. We are recommended by the Scientific Advisory Committee on Nutrition (SACN) to limit our intake of free sugars to 5% of total dietary energy.
THE FAQ FORUM IS “READ-ONLY”, SO YOU WILL NOT BE ABLE TO ADD COMMENTS TO THIS THREAD. IF YOU HAVE ANY ADDITIONAL QUESTIONS OR WOULD LIKE TO DISCUSS ANYTHING RELATED TO WHAT YOU HAVE READ HERE THEN PLEASE RETURN TO THE MAIN FORUM
