24 hour fast

WHEN IS IT OKAY TO JUMPSTART MY METABOLISM. ONLY AT BREKFIST?

I'm going to invent metabolic jumper cables made out of licorice ropes. I'll be rich.

Its complete rubbish that you need to eat often to keep the fire burning. Not only that you could fast for longer than 24 hours an din fact some people do it for 36 Hours (see Lowcarbcory on youtube). You will not go into starvation mode or see a decrease in metobolic rate until 60-72 hours and people should not be fasting for this long anyway the benefits of fasting peak at 24 hours.

And here the proof that you do not need to keep the furnace burning..

1. Myth: Eat frequently to "stoke the metabolic fire".


Truth

Each time you eat, metabolic rate increases slightly for a few hours. Paradoxically, it takes energy to break down and absorb energy. This is the Thermic Effect of Food (TEF). The amount of energy expended is directly proportional to the amount of calories and nutrients consumed in the meal.

Let's assume that we are measuring TEF during 24 hours in a diet of 2700 kcal with 40% protein, 40% carbohydrate and 20% fat. We run three different trials where the only thing we change is the the meal frequency.

A) Three meals: 900 kcal per meal.

Six meals: 450 kcal per meal.

C) Nine meals: 300 kcal per meal.

What we'd find is a different pattern in regards to TEF. Example "A" would yield a larger and long lasting boost in metabolic rate that would gradually taper off until the next meal came around; TEF would show a "peak and valley"-pattern. "C" would yield a very weak but consistent boost in metabolic rate; an even pattern. "B" would be somewhere in between.

However, at the end of the 24-hour period, or as long as it would take to assimilate the nutrients, there would be no difference in TEF. The total amount of energy expended by TEF would be identical in each scenario. Meal frequency does not affect total TEF. You cannot "trick" the body in to burning more or less calories by manipulating meal frequency.

Further reading: I have covered the topic of meal frequency at great length on this site before.

The most extensive review of studies on various meal frequencies and TEF was published in 1997. It looked at many different studies that compared TEF during meal frequencies ranging from 1-17 meals and concluded:

"Studies using whole-body calorimetry and doubly-labelled water to assess total 24 h energy expenditure find no difference between nibbling and gorging".

Since then, no studies have refuted this. For a summary of the above cited study, read this research review by Lyle McDonald.

Earlier this year, a new study was published on the topic. As expected, no differences were found between a lower (3 meals) and higher meal (6 meals) frequency. Read this post for my summary of the study. This study garnered some attention in the mass media and it was nice to see the meal frequency myth being debunked in The New York Times.

Origin

Seeing how conclusive and clear research is on the topic of meal frequency, you might wonder why it is that some people, quite often RDs in fact, keep repeating the myth of "stoking the metabolic fire" by eating small meals on a frequent basis. My best guess is that they've somehow misunderstood TEF. After all, they're technically right to say you keep your metabolism humming along by eating frequently. They just missed that critical part where it was explained that TEF is proportional to the calories consumed in each meal.

Another guess is that they base the advice on some epidemiological studies that found an inverse correlation between high meal frequency and body weight in the population. What that means is that researchers may look at the dietary pattern of thousands individuals and find that those who eat more frequently tend to weigh less than those who eat less frequently. It's important to point out that these studies are uncontrolled in terms of calorie intake and are done on Average Joes (i.e. normal people who do not count calories and just eat spontaneously like most people).

There's a saying that goes "correlation does not imply causation" and this warrants further explanation since it explains many other dietary myths and fallacies. Just because there's a connection between low meal frequencies and higher body weights, doesn't mean that low meal frequencies cause weight gain. Those studies likely show that people who tend to eat less frequently have:

* Dysregulated eating patterns; the personality type that skips breakfast in favor of a donut in the car on the way to work, undereat during the day, and overeat in the evening. They tend to be less concerned with health and diet than those who eat more frequently.

* Another feasible explanation for the association between low meal frequencies and higher body weight is that meal skipping is often used as a weight loss strategy. People who are overweight are more likely to be on a diet and eat fewer meals.

The connection between lower meal frequency and higher body weight in the general population, and vice versa, is connected to behavioral patterns - not metabolism

Source: http://www.leangains.com/2010/10/top-ten-fasting-myths-debunked.html

Here is the section on starvation mode:

4. Myth: Fasting tricks the body into "starvation mode".


Truth

Efficient adaptation to famine was important for survival during rough times in our evolution. Lowering metabolic rate during starvation allowed us to live longer, increasing the possibility that we might come across something to eat. Starvation literally means starvation. It doesn't mean skipping a meal not eating for 24 hours. Or not eating for three days even. The belief that meal skipping or short-term fasting causes "starvation mode" is so completely ridiculous and absurd that it makes me want to jump out the window.

Looking at the numerous studies I've read, the earliest evidence for lowered metabolic rate in response to fasting occurred after 60 hours (-8% in resting metabolic rate). Other studies show metabolic rate is not impacted until 72-96 hours have passed (George Cahill has contributed a lot on this topic).

Seemingly paradoxical, metabolic rate is actually increased in short-term fasting. For some concrete numbers, studies have shown an increase of 3.6% - 10% after 36-48 hours (Mansell PI, et al, and Zauner C, et al). This makes sense from an evolutionary perspective. Epinephrine and norepinephrine (adrenaline/noradrenaline) sharpens the mind and makes us want to move around. Desirable traits that encouraged us to seek for food, or for the hunter to kill his prey, increasing survival. At some point, after several days of no eating, this benefit would confer no benefit to survival and probably would have done more harm than good; instead, an adaptation that favored conservation of energy turned out to be advantageous. Thus metabolic rate is increased in short-term fasting (up to 60 hours).

Again, I have choosen extreme examples to show how absurd the myth of "starvation mode" is - especially when you consider that the exact opposite is true in the context of how the term is thrown around.

Origin

I guess some genius read that fasting or starvation causes metabolic rate to drop and took that to mean that meal skipping, or not eating for a day or two, would cause starvation mode.

Not really advice, just sharing experience. I've tried this before twice- one day I only drank water and tea, and the second time I did it I drank both plain and lemon water. I did lose 3-4 pounds but it was only because it was the day after a binge so obviously it was water weight, as well as food weight and waste.

I'm still deciding if I should fast as I'm already on a deficit from my TDEE?

If you feel fine and don't feel like you're not eating enough, your TDEE number might be off. The key to fasting is eating normally on the days you're not fasting. You just skip a day once or twice a week. When I fast, I don't even get hungry, although I do notice I get psychological urgest to eat, which I over ride.

bumping again....

question....when i open my fast this evening...do i eat one large meal and try and hit as high as poss on calories or do i eat a normal size meal...approx 500 cals?

I eat normally before the fast.