What is the mechanism by which weight loss happens?

[Anonymous]

I understand the concept of calories in, calories burnt but is weight gain based on calories maintained? If I reduced the calories I consumed, my body would draw from my body's stores what it needs. However, if what I've fed my body was sufficient during a particular day, would the stores be accessed even if my calorie intake was less? Lastly, how does eating high calories, smaller portions and eating more often work? Your metabolism is regularly working - does it need to work all the time? I understand the concept behind 'starvation mode' & the slowing down of your metabolism but if you're eating what your body naturally needs, why would it feel 'starved?

[meowcow]

Based on your question, I'm assuming you're looking to achieve sustained weight loss.

There are 2 things you can do:

1. Reduce your caloric intake. This is the BIGGEST factor in weight reduction. It trumps everything else you do, including exercise. If you want to reduce your weight, try reducing the amount you eat, or exchange high-calorie foods for low-calorie. Eating one vegetarian meal per day is a good option. Do it 7-days/week permanently and you're probably going to lose quite a few pounds.

2. Anaerobic exercise. Long distance jogging is a good option. If you lack motivation, join a local running group with people in your running category.

Specific to your question, your body does not access your fat stores unless the body endures prolonged starvation. By prolonged, I mean weeks. Not hours or days.
There are 2 types of fat: white and brown. Brown fat metabolizes quickly and people who are genetically "thin" tend to have a large proportion of brown:white fat. Overweight people tend to have more white fat, which sits at the belly and thighs.

When you have a high caloric intake, the excess is generally stored in brown fat. If you eat even more, white fat cells will be generated and you grow an extra inch around the waist. But when you exercise, it is the brown fat that is used up first. In order for white fat to be utilized, the body needs to adjust (i. e. produce the proper enzymes) and this takes several days. The result is that infrequent exercise (<2 times weekly) does not allow your body to go into white fat-burning mode.

I would suggest reducing your caloric intake to somewhere between 1000-1500 for a female (permanent). Use a caloric calculator. 1500 will seem like very little, but it is equivalent to 3 Big Macs. A single large salad with a lean meat like chicken may only be 200 calories. So you can have 7 of them :)

[HandsomeRaj]

That was awesome, thank you :) :D

[Asker]

I agree - awesome explanation. I've wondered about the fat store issue & this makes sense.

When you hear of people who eat over 2000 calories in small portions spread throughout a day, how is it that they lose weight? These would include full fat foods, but in controlled portions e. g. Steak with salad, full fat greek style yogurt and fruit.

[meowcow]

I should also mention that white fat cells do not "burn" away. When a fat cell grows large enough and replicates into two, they are PERMANENT. Exercise will only shrink the cells, but there is no mechanism for the body to KILL fat cells. This is one of the reasons why exercising away the fat is so difficult. It is easier to maintain a lower body weight compared to gaining weight (more fat cell growth) and then trying to lose it afterwards. You'll likely return to your heavier weight. The only way to remove fat cells is liposuction or other physical removal.

Regarding many small portions, I would recommend still eating proper meals during the day. However, small snack portions might be low calorie items like vegetable sticks. I'm guessing you're trying to fill the empty belly and avoid tummy grumbles.

[Asker]

Thank you although you're stimulating more questions:).
How do contestants on Biggest loser, for ex., shrink their fat cells to almost unseen levels of 'white/brown' fat?
If you are not burning 'off' the fat, how is it that you're shrinking them to weigh almost little to nothing?
No, in fact, I'm one who would regard myself as being on average 15-20lb heavier than needs to be. I had been down to 10lb heavier until I stopped cycling to work. My body has resorted to it's 'resting fat levels.' I'm someone who doesn't need to eat for hours at a time but comfort foods can sometimes be my downfall when thinking/eating them.
I am mesomorphic in frame however I know in myself that I can look quite lean if those 20lbs were 'shrunk.'
From what you're indicating, it seems that I am liable to always be 20lbs 'heavier' unless I get liposuction or shrink the fat. Does Brown fat ever disappear?

[meowcow]

Evolution decided that fat cells were a necessity during times when food was scarce. There was never a need for the body to destroy these cells, so no mechanism ever evolved.

Fast forward to today, where sugar and calories are easy to obtain and our bodies do what they evolved to do. Process extra food into fat cells to store for bad times. Except, we live in an age where food scarcity doesn't exist in first world countries.

When you lose weight, all your fat cells are shrinking. But they will never actually die.

Have you ever heard that diets don't work? And that people regain the weight quickly? When you diet, your body thinks its starving. The natural response is to synthesize more digestive enzymes to extract as much nutrients as possible. When you go off your diet, your food intake skyrockets and your body is creating more digestive enzymes. You absorb more and regain the weight very fast, and may trigger some cells to replicate because they've become too big.

[meowcow]

Neither brown or white fat disappears. But you won't notice brown fat. It's integrated in the muscles to generate energy and heat. White fat is what you see in the breast, thighs and stomach.

For the contestants on the Biggest Loser, the huge amount of weight loss means they will have very flabby skin afterwards.

When there is such a large amount of weight loss for someone over the age of 30, their skin is no longer elastic and that flap of skin is permanent. Many aesthetic doctors will recommend a tummy tuck procedure, which is basically cutting away the excess skin and sewing the skin back together. I believe this is what most Biggest Loser contestants end up doing.

YouTube it. There's a few videos showing contestants getting this after the show.

[meowcow]

Ah here's an example.

Note that a tummy tuck scar is massive and ugly. But it's usually done below the bikini line.
https://www.youtube.com/watch?v=9Soytt4biAY

[Asker]

As questioned, how do people who are morbidly obese manage to shrink their fat cells to an incredible weightless level?
What is the average ratio of brown to white fat in the body? How is brown or white fat utilized if it's never leaving one's body? What is the exact role of fat cells in the body when not used for storage? You mentioned digestive enzymes extracting nutrients... please elaborate further.
Why do people talk about days of eating high calorific foods/cheat days when (If I have you right), it's replenishing the fat cells which have are in the process of shrinking?

[Asker]

Thanks for the vid example. I'm a medic but in Psychiatry hence why all my questions requiring more detail:)

[meowcow]

Its rare that morbidly obese manage to lose much weight. The weight itself impedes the ability to exercise. I guess it's a combo of a restricted diet, stomach stapling, exercise, lipo + tummy tuck.

There's no set ratio of brown:white fat. Depends mostly on diet and genetics.

The role of fat is to store excess nutrients and fat-soluble contaminants. White fat is metabolically inert most of the time. The cell is just sitting there and not using the stored energy. So it is a good place to store damaging contaminants for the long-term. It's also a good insulator.

While people talk about "cheat days", it's probably more of a psychological issue. People need comfort food and I sometimes go to town on a bag of sour cream and bacon chips. It's probably not going to help their efforts at weight loss, but it a cheat day isn't binge eating, so it probably has minimal longterm effects for weight loss

[Asker]

The latest fad is using Garcinia Cambogia or Gummi Gutta fruit. I'm assuming it is an enzyme in the fruit which prevents white fat from being stored?
People also talk about garlic before meals. You're a scientist, what foods are most helpful for fat shrinkage & elimination of fat instead of being deposited as white fat?

[meowcow]

I am not a big advocate of natural products. I am a skeptic when it comes to the belief that eating a capsule of algae will give any benefits beyond lining the pockets of the salesperson with your hard earned money. Most of those products are prevented by the FDA from making statements related to weight loss... etc.

These are noted by "may" statements or careful wording to avoid legal issues.
Example: This product "may" be used to help obesity.
Example: This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure or prevent any disease.

Such labeling can be found on garlic, glucosamine sulfate and pretty much every other natural remedy. I tend to find them based on pseudoscience fueled by bloggers and marketers.

Lipitor is a proven drug that prevents fat deposition and high cholesterol. Its not just for overweight people. It's given to skinny people with high cholesterol too. Might be a starting point. Can be found in genic form

[Asker]

Personally, I have only chosen to prescribe statins in Cardiovascular/Diabetic cases. Those who are using Antipsychotics like Olanzapine or Clozapine can gain exorbitant amounts of weight but I would encourage natural weight loss methods or an alternative Antipsychotic like Aripiprazole prior to opting for a further pharmacological interventions.

I value your point re the lack of scientific evidence re many items which are being cascaded as infallible weight loss tools, but I also believe that nature holds several answers once we seek them.

[Asker]

As a recap (and I appreciate our discourse this St Patrick's day), how does reducing calories result in shrinkage of fat cells?

Thank you.

[meowcow]

There are merits to natural medicines. Many drugs today have their origins from plant extracts such as Taxol (chemotherapy) from the Yew tree, and pyrethrin pesticides from chrysanthemum.

I guess my issue is more that the amount you get from the plant itself, tends to not have beneficial effects in such tiny quantities.

Many products take 1 research article and interpret it as some type of benefit.

I find it a little odd that many people will rant at pharmaceutical companies and their products because of bad science, yet openly embrace natural therapies without question.

Finally, reducing calories won't shrink fat cells. It will help prevent them from growing and replicating more. In order to burn the fat, your daily caloric needs must exceed your intake.

A larger reduction in calories with moderate exercise is better than a minor reduction in calories with tons of exercise. With the latter, you just burn what you eat. Better to not eat it in the first place

[Asker]

Burn fat? Thought fat didn't burn but only shrank?

[meowcow]

I mean burning the fat content in the cells. I did not mean burning away the fat cell completely.

[Asker]

Hello to you again and thank you... you mean catabolysis or metabolisis or the two mechanisms when 'burning' fat? I'm trying to visualize what happens...
I seem to not be visualizing what happens once brown/white fats nutrients have been used. How is it that they are used when eating less food/calories? By eating at lower caloric levels e. g. 1500 instead of the recommended 2000, is that putting your body in a situation where it NEEDS to draw out more nutrients from the fat cells?
I've always had the impression that fat is excreted out of the body when it's fat is being catabolized.
Please clear my mind of this mystery!

[meowcow]

Without getting too detailed, when the body needs energy, it coverts sugar and starch from the diet to glucose. This requires little energy input, so it's the primary process. When there's not enough, the your body will use the fatty acids and amino acids from your diet.

In contrast, fats are a storage form of energy. It cannot be directly used and takes time (days) to convert from fats --> glycerides --> fatty acids.

If you reduce caloric intake and increase exercise, your diet won't have enough calories. The body switches to fat metabolism to supplement the energy deficiency. The fats slowly get used up, shrinking fat cells. If the body runs out of fat, it will switch to muscles under extreme starvation conditions.

[Asker]

Makes perfect sense. Your body gets to a maintenance level when you've kept at a particular weight for x amount of time. (?2 weeks) When you eat less calories than your original maintenance weight, your body withdraws nutrients from its storage facilities e. g. fat to compensate for the deficiency of calories you WOULD have been eating to keep at your original maintainence weight.
This is why if you're overweight and lose weight, your body will do all its power to get back to that weight you attained. You will always run the risk of returning to that weight as the fat cells which shrunk are awaiting an opportune time to resort back to the highest maintenance level reached. More fat can be gained during these periods as the body wants to have enough for future 'rainy starved' days...
When you say that those who have become morbidly obese deal with flabby skin once they've consumed their bodies excess nutrients, I'm assuming this is subcutaneous fat which is 'starved' of nutrients?

[Asker]

Or rather subcutaneous fat which is lying with the skin?

[DanteSparda]

Since I have limited character limit , I'll post you some links which might answer your question :)
-voices.yahoo.com/...-fat-burning-mode-2148744.html

Check out this blog
-https://www.leangains.com/search/label/Fat%20Loss

[Asker]

Thank you Dante. Your advice has added to my new found knowledge. Truly gaining a great deal from you guys! Thank you very much! Makes sense about keeping the body constantly in metabolisis mode..

[Anonymous]

The tips they say really make a difference are 1. Reduce carbohydrates. 2. Do not eat at night.

[Asker]

Carbs are also fruits and veg too & I don't quite agree with the theory of not eating late at night. Thank you for your insights though!

[GoldCobra]

Uhh u have to est less than your body is accustomed to and u will lose some fat. Takes time though. Cardio helps. So does weight training

[GoldCobra]

Eat* not est

[Asker]

Thank you, makes sense