interessant stukje

[Viranelly]

Ik kwam net een interessant stukje tegen over koolhydraten en eiwitten:

Generally when people cut out carbs they increase protein, the reason why cutting carbs and replacing with protein offers advantages for weight loss is due to the fact that protein does not equal 4 net calories as most people believe. 25 grams of protein (100 calories) will yield only 57 calories to the body, however 25 grams of carbohydrate (100 calories) will yield 93-98 calories to the body. As you can see by substituting 25 grams of carbohydrate for 25 grams of protein you are also reducing overall calorie intake by around 40 calories.

Als dit klopt dan moeten mensen op een low carb / high protein dieet dus nog meer eten om aan te komen?

[sf01]

staat er een bronvermelding bij?

[Viranelly]

staat er een bronvermelding bij?

Jep, maar de link is dood.

Komt van een ouder topic op bodybuilding.com

[marnop]

Geef even de bron of link Viranelly.
Dat je netto minder cal over houdt om het lichaam te voeden wisten we al, maar zo'n groot verschil.......Ik vaag me af hoe het gemeten is en in welke situatie.

[Viranelly]

vanaf de derde reply:

Has anybody ever been on a 500 cal/day deficit and not lost weight... - Bodybuilding.com Forums

alleen de link die daarna gegeven wordt is dood

[marnop]

Gaat alleen over de hoeveelheid eiwitten die je teveel neemt.
Daarvan wordt van elke gram dus 2cal omgezet naar glucose.

[dynobet]

heeft te maken met de thermische waarde van eiwitten, koolhydraten en vetten. maar de absolute waarden die jij noemt kloppen niet.

Thermic effect of food: the cost of processing food for storage and use.

Thermic Effect of Food (TEF)
The thermic effect of food (TEF, also known as Dietary Induced Thermogenesis or DIT) refers to the slight bump in metabolic rate that occurs after eating, due to processing and utilization of the ingested nutrients.

For example, protein has to be broken down and processed in the liver which requires energy. As well, the simple act of eating protein stimulates protein synthesis in various tissues (organs, liver, muscle) as well. All of which takes energy.

Carbohydrates get broken down to glucose, which goes through the liver, some processing, etc. Fat undergoes the least processing. There are exceptions such as medium chain triglycerides (MCTs) which undergo quite a bit of processing in the liver, causing a slight bump in metabolic rate (via TEF) in the process.

As it turns out, different nutrients have different individual TEF’s. Protein turns out to have the highest, to the tune of 20-30%. Meaning that of the total protein calories you eat, 20-30% is lost in processing. Carbohydrate stored as glycogen requires about 5-6% of the total calories. Carbohydrate converted to fat (which generally doesn’t happen in very significant amounts) uses up ~23% of the total calories as TEF. Most fats have a tiny TEF, maybe 2-3% (because they can be stored as fat in fat cells with minimal processing).

Since it’s usually impractical to sit and figure out the individual TEFs for each nutrient, the normal estimate used is 10% of total caloric intake. So if you consume 3000 calories per day of a relatively ‘normal’ mixed diet, you can assume that your TEF is about 300 calories per day or so. You also generally find that, with the exception of extreme diets (such as all protein), shuffling macronutrients has a pretty minimal overall impact on metabolic rate via TEF.

For example, consider the difference in TEF for carbs versus fat: 5-6% vs. 3%. That means that, for every 100 calories of each you ate, you’d burn 5-6 or 3 calories. So if you replaced 100 calories of fat with 100 calories of carbohydrates, you’d burn a whopping 2-3 extra calories via TEF.

If you replaced 1000 calories of fat with 1000 calories of carbohydrates, you’d burn 20-30 more calories. If you were able, by some means, to replace 2000 calories of fat with carbohydrates, you would burn 40-60 more calories via TEF.

About the only time that TEF can become considerable is when you replace carbohydrates or fat with protein. For every 100 calories of carbs/fat replaced with protein, you’d expect to burn about 25 calories more (30 cal for protein vs. 3-6 for carbs/fat). So a doubling of protein from 60 to120 grams/day might increase TEF by 80 calories/day. Triple it to 180 grams/day and TEF could increase by 150 calories. The 20-30% TEF of protein can become even more significant at extreme intakes.

In all but the most extreme diets, protein stays fairly static and carbs and fats are shuffled around; the effect is typically minimal in terms of TEF.
Finally, I should mention that some research has found that insulin resistant individuals may have an impaired TEF response to eating, with a rough 50% reduction occurring. This could conceivably become significant. For example, on a 3000 cal/day diet, the estimated TEF would be 300 calories. Cut that in half and you only get a 150 cal/day increase in energy expenditure via TEF. Over a month’s time that would amount to 4,500 calories or about 1.5 lbs difference. I’d assume that correcting the insulin resistance by losing fat, lowering insulin and various other interventions would correct this defect and allow TEF to work normally.

ik denk dat je dit bedoelde.

[marnop]

Volgens wat er bedoeld wordt kloppen de cijfers van Viranelly wel.
Maar of het wel helemaal zo relevant is....de tekst is van 1915 oid.

.................................................. ...

As an average result of five experiments it was found that 58.0
per cent of the muscle protein had been converted into glucose.
The average protein G : N ratio obtained by dividing this value
by the amount of nitrogen contained in 100 grams of protein is
3.53 : 1. If from the protein nitrogen 0.34 gram be deducted for
nucleic acid which in all probability yields no glucose, the ratio
3.60 : 1 may be accepted as representing the relation between the nitrogen
contained in human muscle protein and the glucose originating
from the same in metabolism. The muscle proteins constitute the
chief bull; of body protein. The average amount of metabolic
glucose yielded by other body proteins (serum albumin, gelatin,
fibrin) is 57.7 per cent. It may on these grounds be properly concluded
that the proteins of the human organism collectively may yield
a maximum of about 58 per cent of glucose in diabetic metabolism.

With regard to this mode of experimentation the question may

From the above it is evident that not more than about 60 per
cent of body protein, corresponding to a urinary G: N ratio of
about 3.4 : 1, can be converted into glucose. The statements in
the literature of much higher ratios, such as 5 : 1, and a correspondingly
greater sugar formation from the proteins of the

organism, can therefore be no longer accepted.

bron: http://www.jbc.org/content/23/1/77.full.pdf

[Patricia86]

Geen idee. Koolhydraten kunnen je stofwisseling versnellen, eiwitten juist vertragen.
En nee, geen officiële bron of deftige onderbouwing.

Toen ik ongeveer een half jaar op low carb zat, boekte ik gewoon minder vooruitgang dan nu. Daarbij was ik een stuk trager (qua energie, maar ook in mn hoofd). Ik eet nu hetzelfde aantal kcal, en ik merk weer vooruitgang (+veel meer energie om netjes te trainen en mn dag te volbrengen).
Terugkijkend weet ik gewoon zeker dat ik destijds teveel eiwitten at. Niet alleen omdat ik geen vet meer verloor, maar ook omdat mijn huid veel slechter was, dan nu (al wou ik dat destijds niet inzien).
Hoewel ik met mijn trainingen nu veel dieper kan gaan, is mijn herstel gewoon nog steeds erg snel.

[maar7en8]

Geen idee. Koolhydraten kunnen je stofwisseling versnellen, eiwitten juist vertragen.

naar mijn weten is dit juist andersom

[dynobet]

als je langere tijd low carb zit, zonder carb refeeds, gaat je stofwisseling omlaag omwille van de leptine die ook flink zakt. Leptine heeft een aardige invloed op onze stofwisseling.

Maar als je niet low carb zit, dan is dit niet het geval. Verder denk ik nog steeds dat The termic effect of food, de grootste invloed heeft op onze stofwisseling (op gebied van voeding).

[Kevster]

Ik denk ook dat het komt door het feit dat eiwitten (die 4kcal KUNNEN opleveren) alleen uitzonderlijk verbouwd worden naar energie. Ze zijn nagenoeg niet bestemt als energiebron maar als bouwsteen.

[dynobet]

Ik denk ook dat het komt door het feit dat eiwitten (die 4kcal KUNNEN opleveren) alleen uitzonderlijk verbouwd worden naar energie. Ze zijn nagenoeg niet bestemt als energiebron maar als bouwsteen.

exact, dit artikel zegt eigenlijk genoeg: Metabolic Rate Overview | BodyRecomposition - The Home of Lyle McDonald