Eat more fat to lose weight?

UPDATE: I am in process of updating this post as there were a number of mistakes – so if you find it confusing it is probably because it is. Will re-post once I got it down more clearly (v2.0 here)

Tim made some interesting remarks in the comments of one of my previous posts:

If you’re looking to lose weight, I would up the fat and lower the protein and further lower the carbs …. Dropping carbs to 20% or lower will really help

This got me thinking: from my limited knowledge of the bodies energy pathways the following nutritional strategy would actually make sense to me:

  • Use fat for the majority of the body’s energy needs (more precisely: for all aerobic energy needs apart from the brain)
  • Use carbs for – and only for – the anaerobic energy needs and for the brain as it can not use fat and/or proteins
  • Avoid using protein for producing energy – it is meant to help you build your body, nothing else

How would this look in practice? Assume I magically figured out that my aerobic base requirement. First order this should be whatever the formulae gives for sedentary lifestyle, in my case (ca 95kg lean body weight, 186cm) I would say this is about 2000 cals. A certain percentage of this should go to the brain – it seems about 20%, or 400cals in my case. 1g of carbs is 4cal (same for proteins, fat is 9cals), so 400cal is 100g of carbs. Let´s call it 125g to account for the odd anaerobic needs that happen throughout the day, and not to cut it too short with the brain.

Protein requirement is about 0.5-1g per kg of lean body mass, (Update: according to the Primal Blueprint page87ish, you need 0.7-1g per pound of bodyweight. For reference, 1kg=2.20pounds, so I’d say I need 150-200g protein per day) which would give 50-100g 150-200g give or take in my case, providing an energetic equivalent of 200-400cals 600-800cals. Let’s assume I want to be in the midpoint of that, being 75g / 300 cals. So in summary the dietary plan under those assumptions would be as follows:

Dietary plan in periods without significant training

  • Overall energy consumption of 2000 cals/day (186cm height, 100kg lean body weigth)
  • 125g of carbs provide 500cals, or 25% of calorie requirements
  • 75g 150g of protein provide 300 cals 600cals, or 15% of calorie requirements
  • The remaining 1200 calories (60% of total) 900 cals are provided by 133g of fat; if I want a calorific deficit this it is where it should come from, ie if I am on a 1600cal diet then I only eat 800 cal / 90g of fat

In periods with significant training one would need to estimate to which extent that activities are aerobic (in which case they should be provided for with fat), and to which extent they are anaerobic (in which case they should be provided for with carbs). Also, if strength training with a significant tear-down / build-up of muscle mass is involved then one might to go for the full 1g or proteins rather than the 0.75g budgeted for above. I assume a one-hour training period with a half-hour CrossFit style all-out exercise. Lets say this consumes about 600 cals, 400 of which are in carbs. This would lead to the follwing supplementary requirements: protein 25g / 100cal (which incidentally is about one scoop of a typical protein powder), carbs 100g / 400cals, and fat the remainder, ie 22g / 200cals.

Dietary plan in periods with significant training (Update: tbc)

  • Overall energy consumption of 2600 cals/day (186cm height, 100kg lean body weigth)
  • 225g of carbs provide 900cals, or 35% of calorie requirements
  • 100g of protein provide 400 cals, or 15% of calorie requirements
  • The remaining 1300 calories (50% of total) are provided by 144g of fat (or 900cals / 100g of fat on a 1600cals diet)


  • Calories 1600 / 2200 on regular / training days if on a diet, 2000 / 2600 otherwise
  • Carbs 125g / 225g regardless of whether on a diet or not (update: PB suggests 100-150g/day – might need to revise)
  • Protein 75g / 100g 150 / 200g ditto
  • Fat 90g / 100g TBC if on a diet, 135g / 145g otherwise

Now of course the proof is in the pudding (pudding? is pudding paleo?) so let’s see how this works in practice. Will keep you posted…

6 thoughts on “Eat more fat to lose weight?

  1. Hey Thor, thanks for the mention as always.

    One other thing to keep in mind (no pun intended): many brain cells can adapt to run off of ketones; there are plenty of people eating VLC or 0 carb diets that have normal brain function. Your body will also readily convert protein into glucose via gluconeogenesis as needed (the efficacy of this is usually 60-70%). (See the Primal Blueprint for a more detailed discussion)

    And here’s a tip: I’ve found the best thing post-workout (and here I mean half-hour long Tabata sessions that leave me drenched) for repleneshing used glycogen is a sweet potato. Cook it however you like – I’m a fan of baked crisps with lots of guacamole. Our bodies are great at using starchy vegetables to replenish glycogen, plus they taste awesome – stews, baked, mashed with lots of garlic butter and heavy cream…..*wipes drool off keyboard*

    It looks like you’ve got a great plan worked up – please do keep me posted! I’m super-excited for you and to see how it works 🙂

    • Thanks Tim! So you wouldn’t do protein post-workout? I tend to do something like 1scoop of protein powder and one scoop of milk powder (or actual milk if I am at home), plus an apple or so

      • I personally like to eat an actual meal afterward – I generally eat only 2 meals a day, so this works out well for me. Plus, if I’m only eating twice, I don’t need to worry about working out on a full stomach!

        I’ve read in a few places that the BCAAs in eggs make them an ideal pre-workout (i.e. 30 minutes before) snack for fueling muscle growth.

        There seems to be some interesting benefits from fasting post-workout too, see:

        (One of my workout days usually falls on my weekly fast day – I’ve seen a drop in endurance but no other negative effects in terms of recovery, etc.)

        But all in all, I should have been more specific: I’ll generally have a full meal, with all the animal protein that entails, and then have a sweet potato along with it. Dairy is also a good choice if you’re an athlete/looking to gain muscle and your system tolerates it well – the calories in it are readily converted to glycogen, like those in starchy root vegetables.

  2. Pingback: Eat more fat to lose weight? – v2.0 « Thor Falk

  3. Pingback: Paleo – 3 days in « Thor Falk

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