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TVP_lab26 karma

We haven't received any criticisms from activists so far, and hopefully we won't in future! As scientists, we are not trying to push any public agendas, but simply to construct hypotheses and try to answer them in a scientific manner.

Another important point here is that the amount of fat in any given individual will not directly pose a risk of disease. There are some individuals that have a lot of fat, but as it is functioning properly, they are metabolically healthy! Conversely, there are some slim individuals with very little or no functional fat tissue that are very insulin resistant.

Sam from our group wrote a review a while ago titled 'It's Not How Fat You Are, It's What You Do with It That Counts'. We still think this statement holds true!

Link to review: http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.0060237

Kasparas

TVP_lab21 karma

Hey the realplanetX

This is a great question.

Fat cells have three major functions:

  1. They store calories long term. A Kg of fat has more than twice the calories as a Kg of carbs or protein. This means if you need to cart around an energy store it is more efficient to use fat than other types of storage molecule.
  2. Fat cells secrete loads of hormones that control different aspects of how our bodies work. For example, the hormone leptin is produced by fat cells. It tells the body if it has enough nutrients to do certain things, for example if you have really low leptin levels women temporarily cease being able to reproduce. This would have evolved to prevent animals getting pregnant when you lack enough fat reserves to support the pregnancy.
  3. Fat cells buffer our daily lipids. After we eat insulin tells fat cells to take up the fat we have eaten and store it. We can then burn the carbohydrate parts of our meals. Then, when we are asleep the nervous system tells fat cells to break down and release it into the blood stream. These fatty acids that are released by adipose tissue can then be used by organs like muscle and heart for fuel.

In this article we focus on aspect 3 - fat cells as lipid buffers.

Cheers,

Sam

TVP_lab13 karma

Hey Bokbreath,

There are several ways fat can be dysfunctional, but what we focus on in this paper is its daily role in controlling what the body does with the fat you eat.

Healthy fat (adipose tissue) takes up the fat we consume and stores it until it is needed for fuel, such as at night when we are asleep. When obese people eat a meal their adipose tissue does not take up the fat. Instead, the fat is directed into other organs, such as the liver and muscle where it causes insulin resistance.

Importantly, the adipose tissue of obese people is also bad at releasing fat when they are asleep, meaning that obese people have to use lots of glucose when they are sleeping to provide energy.

So fat that is dysfunctional is bad at both taking up and releasing fat, leading to the body using the wrong nutrients at the wrong time.

Sam Virtue

TVP_lab11 karma

Hey coreyrenton,

This is an interesting idea. There are suggestions out there that yo-yo dieting (ie losing then gaining weight repeatedly) may be bad for you, but I hadn't thought about it impacting on adipose tissue depots differently.

We haven't done this personally, but I had a quick look at the literature there are a few studies out there suggesting weight loss and regain can affect body fat distribution. Some other studies suggest that this does not happen, so it seems that it is not currently clear.

However, if I understand what you are asking, when we lose weight we don't necessarily lose fat cells- the cells have a half-life of about 8 years. What happens is the cells shrink as they empty of fat. They can then refill.

Cheers,

Sam

TVP_lab9 karma

Hey Hendrikto

  1. I am not a medical dr, so I don't come across individuals who have lost a lot of weight!

  2. Physics caused this. 25 kg of fat is about 55kg of pure sugar! So that is about 550 litres of coca cola.

If you were drinking that about a 1.5 liters of coke a day (which based on your post sounds likely if you were drinking only sugary drinks) then you were consuming 150 grams of sugar, or 600 calories just from the drinks.

If you stopped consuming the 600 calories a day without changing the other aspects of your diet you could lose that much weight.

Cheers,

Sam