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About Losing Weight and Fat

If your calorie maintainace is at 2000 cal, what would be optimal macros for losing fat? If you would eat pure sugar at 1500 cal you would still lose weight as muscle a bone mass but gain fat mass, so what is the optimal macros for fat loss?

You asking or quizing?

This is not correct. An individual running a 500 cal/d deficit would not gain any fat, no matter how his/her caloric intake was sourced.


What would happen then? Im a bit confused, in Damon Gameau’s “That Sugar Film”, the guy keeps his caloric intake the same as before but loads up on way more sugar, and his weight gain was over 8kg with most of it being fat in 60 days.
How can he gain so much weight (fat) if his caloric intake is the same as before CICO doesn’t make much sense here.

And let’s say you do as i said only eat sugar in a caloric deficit, would’t you gain plenty of visceral fat? This my thoughts after watching Dr. Robert Lustig’s “Sugar: The Bitter Truth”

Or let’s say you get your calories only from etanol (I know these scenarios are not realistic but hypothetical), wouldn’t you still lose weight as bone and muscle mass but gain visceral fat?

Sick, KFC every day for me… But only 1500… Calories… Worth. Australian KFC is fantastic, don’t knock it till you try it. I didn’t like KFC in America, but in Australia the chicken is to die for!!! South African KFC is also fantastic, but South Africa as a country is a terrifying place to visit. I’m a bit of a KFC connoisuer, having tried kentucky fried chicken from many countries

In terms of cardiometabolic health, surely eating like shit (albeit in a deficit) can’t be good for you. I’m not a fan of the IIFYM rhetoric. Eating sugary food/fried food all day (albeit fitting designated dietary parameters) may be effective for fat loss, but from a health standpoint surely there’s gotta be some rammifications right?

I’m not familiar with that film, but a quick Google search indicates the ‘data’ it presents were not gathered in a rigorous manner. On the other hand, diet-related data that was gathered in a rigorous manner indicate that changes in body weight track very, very closely with caloric balance, irrespective of the macronutrients involved.

In contrast, the evidence also indicates that changes in body composition can be influenced by macronutrient distribution. And, tying this in with your initial question regarding ‘optimal macros for fat loss,’ a better way to think of it would be: What are the optimal macros for muscle retention while in a caloric deficit?

In that regard, IMO the diet-related key to maintaining muscle is maintaining adequate protein intake. People can disagree as to how much protein is ‘adequate,’ but most would probably consider a daily intake of 1 gm of protein per pound of bodyweight to be a reasonable amount. So, set protein at 1 mg/lb/d–no less. As for the rest of one’s caloric intake, it should take whatever combination of protein, carbs and fat you like–just make sure it adds up to less than your caloric output.

The other key to retaining muscle while in a caloric deficit is resistance training. Excess muscle is metabolically expensive, and thus the body will shed it when caloric intake drops. The only way to keep the body from doing so is to convince it (the body) that the muscle is needed. And the only way to convince the body that muscle is needed is to put significant metabolic and mechanical stress on the muscle on a regular basis.


Without a doubt. If someone literally ate nothing but sugar, they would eventually die of malnutrition, no matter how much they consumed.


I remember you writing at some point that a coach had you eating a fixed amount of protein which wasn’t tied to your bodyweight but a fixed number. Like 200g. I’ve been inadvertently doing that (which is higher than my g/lbs requirement) and it’s been working well for me. Always wondered about that but at the time you were reluctant to share details. Thanks all the same!

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There is actually a study from back in 1975 - the days when medical ethics weren’t quite as constraining - which may explain this.

Basically subjects were fed intravenously, using protein, glucose and other nutrients such as sodium, calcium, magnesium, etc. They then started to withdraw the various components of the feed to see what effect it had on growth of bone, muscle and fat tissues. What they found is that when either protein, sodium or phosphorus were withdrawn, bone and muscle growth ceased. The remaining energy was converted into fat.

This study showed abundant glucose alone was enough to drive fat mass. It also highlights more flaws in the whole CICO theory, which is even more remarkable given such knowledge being in the public domain for the last 45 years.

EDIT: I should cite the ref - Elemental balances during intravenous hyperalimentation of underweight adult subjects (Rudman et al, 1975)

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