I was reading below and have a doubt.


So to lose weight "energy in" should be less than expenditure . So they advice us to eat more low energy density foods (LEDF) to feel full , so hunger will be satisfied and also the in/out formula.

1) What is the relation of hunger and energy ? If we fool hunger by eating LEDF does this not stop having the energy need for body ? Isn't hunger is the natural signal for energy requirement ?


Back before Costco, Lean Pockets, and Pepsi I'm sure the relationship between energy levels and hunger was a bit more straight forward.

Hunger is caused by a peptide (cousins of a hormone) called ghrelin. A lot of things can cause this to rise and fall, including sleep schedules. Most people notice that on days where they get poor sleep, the next day they will be much hungrier and make bad food choices. That obviously has nothing to do with the energy reserves you started the day with, and if food really stopped hunger in the short term then simply eating a big breakfast would stop the cycle.

What is the relation of hunger and energy?

It's very intricate. For most people, feeling hungry is because of insulin spikes:

...that elevations in insulin produce increased hunger, heightened perceived pleasantness of sweet taste, and increased food intake.

It's a bit of a viscous cycle because eating simple carbohydrates (bread, rice, sugar, flour, etc) produces insulin which makes the food taste better and makes you hungrier. Insulin is also an anabolic hormone that provides for fat storage.

If we fool hunger by eating LEDF does this not stop having the energy need for body ?

No. You most likely have far more energy than your body needs to get through the day and possibly through the next month or two, just in fat and sugar (and to a lesser extend muscle) reserves.

If you were a 4% body fat hunter gatherer living 300K years ago then yes, you really would want to ensure that you're sucking down every calorie you can get your hands on and never want to pass up a meal. Unfortunately, we share the same biology of our ancestors and food marketing companies know how to work with this.

Isn't hunger is the natural signal for energy requirement ?

Not for the vast majority of humans in the developed world. As shown above, hunger can exist because you ate too much bread or didn't get enough sleep. I don't know if there is any data on it, but I would venture to guess that the average westerner might never have had hunger caused by anything other than spurious signals, most of which are engineered by food companies.

If you get a chance, I'd recommend watching (and sharing) the movie Food, Inc.

  • I think one should be cautious not to be an insulin alarmist. Insulin causes fat storage, yes, but it also causes storage in muscles, the ratio depends on the insulin sensitivity in your muscles among other things. It's also very reasonable that insulin leads to fat storage, you need some mechanism to put the carbs to use or you would pee glucose (as diabetics do without insulin.) There are also studies showing that insulin decreases hunger! Also, fat intake also leads to fat storage, energy doesn't get wasted, it will either be used or stored, regardless of form. – Mårten Feb 17 '15 at 12:09

An interesting question you have posted. In essence these low energy dense foods (LEDF) actually work well if you look at the evidence for them and they do not compromise or cheat your hunger. For instance a study followed people for a year and found this strategy beneficial.Follow this link for details of this study: http://www.ncbi.nlm.nih.gov/pubmed/17556681. The LEDF are also nutrient dense and when followed well can help you eat healthy and even attain your energy needs for instance look at this http://preventcancer.aicr.org/new/images/photos/various/EnergyDensityPR.jpg. In the link of that picture you will realise that he picture shows an example of LEDF which contributes about 1500kcal and just adding a little to these foods one can easily get to the 2000kcal daily requirement of energy intake. Unlike filling up ourselves with high energy dense foods which will do not quickly fill us up and thus makes us take in more calories than needed.

Thus its clear that if we first look at samples of LEDF's before we start to think of hormones like ghrelin and also evaluate the practical evidence regarding, LEDF's are a sustainable and effective strategy for weight loss.

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