T Nation

Where Do the Calories Come From?


I see a lot of talk about low carb/high fat diets. I just have a question (and it is not a loaded one to start an argument, I'm seriously wondering what you guys do).

Hypothetically, let's say we have a 200 lbs man at 8% body fat percentage. His BMR is roughly 1840 calories. Assuming a semi-intense training schedule we will multiple by an activity factor of .7. Thus, his daily caloric intake is somewhere around 3128.

If he is taking in a 1.5 grams of protein per pound of body weight, he will consume 300 grams of protein or 1200 calories.

That leaves 1928 calories. Assuming he is taking in 30% fat. He is consuming 1043 calories from fat. All in all, protein plus fat equals 2243 calories, and he has a deficit of 885 calories.

If he consumes these in carbs, he is taking in 222 grams of carbs a day. To me, this seems like a pretty high carb day.

If he lowers his carbs, does he increase his fat or protein? Protein doesn't seem to make sense because he is probably already pushing the threshold of what his body can absorb in a day. If he raises is fat, he seems to be taking in a lot of fat, which may impact his insulin sensitivity.


Dude the whole premise behind a low carb/high fat diet is the fact that it's LOW CARB. If your eating 222 grams a day in carbs that is not "Low Carb", Low carb would probably be at least 100g or less and most importantly under 50g to be in ketosis, one of the main reasons for going low carb.

You up the fat in this case, fat cals should be greater than protein cals at least for the first 2-3 weeks on a low carb diet. As long as the fats are healthy especially the saturated fats (which cause?s insulin resistance if consumed in excess and from crappy sources) your insulin sensitivity will actually be better while low carb.


since when is 220g of carbs a lot for a 200 lb, active man?


You increase both. If your on <50g carbs/day a typical breakdown might be 35%p/60%f/5%c. Even if your body can't utilize the protein, you still eat it. And on a keto diet you become more insulin sensitive. So much that sometimes when you eat a huge amount of carbs its unbelievably hard to stay awake.

And 222g grams of carbs is not low. Low is considered about 60-100grams/day and keto is under that.


the problem with using words like "low" and "high" is that it's completely subjective. assuming one is a 200 lb male who is weight training and eating to maintain he should be consuming approximately 16 cals per lb, or 3200 calories. 220g of carbs provide 880 calories (assuming we are counting "net carbs") 880 calories is less than 30% of his total caloric intake. hardly what I call a "high carb diet".


Where did you get this dumb idea?


Fats, especially saturated fats have been shown to damage the insulin receptors of muscles. This causes a build up of glucose in the blood stream which causes more insulin to be produced. Insulin triggers the release of lipoprotein lipase which blocks fat cells from breaking down. All in all, fat cells become more receptive to insulin if the diet is high in fat.


IME I can go up to 100g of carbs of day, and still end up in ketosis, albeit it takes slightly longer.

300g of protien is 1350kcal.

Another point is that if he is dieting he will want to cut atleast 300-500kcal from his RMR everyday leaving 2628kcal.

Divide the remaining cals by 9.7kcal and you get
132g/fat day.

I dont see the problem....


Why would low carb diets be proven to lower insulin sensitivity than?


So wait - fat damages muscle insulin receptors, but enhances the ones on fat cells? What, exactly is the difference between the two receptors for the same molecule?

Also lipoprotein lipase breaks down lipoproteins (so called "cholesterol" LDL, HDL, ect) to be used for storage or energy. It does not block fat cells from doing jack.

In addition, ingesting fat does not cause your pancreas to release insulin. Your body can metabolize fat just fine with zero insulin.

I would advise you to recheck some basic physiology.


Monounsaturated and polyunsaturated fatty acids IMPROVE insulin sensitivty through modifications in the composition of cell membranes. So upping fat is not a bad thing. However, there's no need to completely eliinate carbs when maintaining. Many individuals who are lean do fine with moderate levels of carbs for maintenance.


But when did he say anything about a low carb diet in the original post? Why are we automatically recommending a low carb plan?

What if the guy described in the original post is very insulin sensitive and doesn't upregulate fat oxidation well? He gets fat!

220g carbs is not a lot for an active individual burning that many calories.

Here is how I believe to set the diet

(1) set calories

(2) set protein

(3) determine adequate carb intake by goals, individual factors (responsiveness, insulin sensitivity, size, activity, etc)

(4) the rest is fat

Percents are not a meaningful way to set up a diet and the body doesn't digest food in percents.

Eventually he will end up in Ketosis if he doesn't consume enough carbs to support activity. Even at 200g a day. The 30g/day figure came out of nowhere and isn't really based upon anything.

Anyway, even for someone maintaining, daily expenditure is going to vary. Trying to eat the same amount is not giving the body what it wants. He should set up a dieting system and eat more food and carbs when he is hungrier, which will follow training and biorhythms and all of that good shit. Some days your sleep, activity, hormones, whatever are going to cause a big difference in what your body wants. In the post workout period, or after several days or longer of a more intense plan, the body may need more food and different kinds of food at random times.

Hence the recommendations to eat extra calories from sugar and protein post-workout, and refeed or cheat day occasionally. Now learn to integrate these into your actual needs and you will do a lot better. Most BB pros don't finish their workout and need the exact same food and measure it out the rest of the day.

In the same way that they "know" how to alter training for the best results. Some creativity and observation is required. It isn't about a system, the stuff you read and learn explains WHY things happen, and can provide general guidelines, but at the end of the day I think it's important to keep in mind your actual goals and the point of what you are doing, otherwise you are just cheating yourself.

I strongly feel that a lot of people taking a really anal approach would benefit from learning to be more flexible and just setting basic guidelines, eating good food when hungry, and seeing how they respond. Learn about your body and then tweak your programs more effectively to your individual needs.

My opinion.


I'm not claiming to know everything, but I've read and heard that saturated fat damages muscle cells differently than fat cells. I may be wrong.

As for lipoprotein lipase, when lipoprotein lipase is high it keeps fat cells from being broken down for energy. Thus, you don't burn fat; you burn muscle.

As for increasing insulin, when you eat saturated fats it makes your muscles less insulin sensitive because of the damage to the muscle cells. When you later eat carbs, your body produces insulin. When your body tries to refill glycogen stores, it has a hard time because the muscles are less receptive.

This causes a backlog of glucose in the blood stream. Your body recognizes this and puts out more insulin to help deliver the glucose. All in all, while directly eating saturated fats does not signal for the pancreas to release insulin, indirectly it does because of the insulin resistence.


Saturated fat does negatively effect insulin sensitivty but it should not be completely avoided like the plague because it is aids proper hormone functioning. Also, MCTs do not negatively effect insulin sensitivity. So, if you're really concerned choose mostly low fat protein sources and use coconut oil to get your saturated fat. Also very good for the thyroid and has other benefits. And get plenty of mono and poly unsaturated fat which improve insulin sensitivity and have many other health benefits.


That's what I do JSbrook, and that's my understanding as well


I try to have 1/3 of my fats be "good" saturated fats. I just find it hard to limit my self to "good" saturated fats and still take in enough calories. Yeah I add olive oil to everything, but that leaves me still feeling hungry because my food has no real substance.

Currently, I eat about 50% to 75% of my carbs during breakfast or pre-/post- workout. But it seems like the remaining 25% can still be "a lot" of grams spread out over the day. I just can't get low enough.

If you had a lot of fiberous carbs (beans, whole fruit, etc.), wouldn't this stop on of the main negatives of carbs -- insulin spikes. Thus, it wouldn't sabotage your cutting goals? Or are carbs bad in and off themselves?


carbs are not bad in and of themselves, nor is elevated insulin anything to get worked up about.

if you only know one thing about fat loss it should be this: so long as one is in an energy deficit, the body will not store fat. period. no matter what.

so enjoy eating carbs, morning, afternoon, and night. as long as you're still in a deficit, you will lose fat.


Everyone has different levels of carbs they do well on for cutting. After veggies, beans and legumes are probably your best carb choices. You are hungry after a meal of solid protein, high fiber vegetables, and unsaturated fat? With perhaps some saturated fat. It's normal to be a little hungry when cutting/in a caloric deficit. I always am. But those are good filling foods. Make sure every meal contains veggies and fiver.


Mmmm, that's an oversimplification. But caloric deficit is still the most important thing. Nonetheless, macro nutrients and food timing certainly impacts fat loss. And certainly body composition.