T Nation

Low-carb vs. moderate-carb diet

Although low-carb diets are very popular these days (I had pretty good results with the T-Dawg Diet myself), a few guru’s (including JMB) are not huge fans of a low-carb diet.

Which leads me to wonder, which type of diet is better for fat loss? A low-carb approach (eg. T-Dawg) or a moderate-carb diet (eg. Don’t Diet)?

Here are what I consider the pros and cons of the low-carb approach:

Pro: Faster weight loss (MAIN pro)
Pro: Increased insulin sensitivity

Con: A lot of the initial weight loss is water and glycogen
Con: You feel like crap physically and mentally. Flat workouts
Con: Fat is not burned efficiently without sufficient carbs (someone correct me if I’m wrong on this)

Would something with a higher carb (eg. 30P/40C/30F or even 40P/40C/20C) be better?

Correct me if I`m wrong, but I am pretty certain that a low-carb diet reduces insulin sensititivity.

I still follow the same train of thought as JB on this particular issue–as I do most issues. This is primarily due to the fact that I think anyone should base his/her nutritional plan on something that can be followed long-term. This is why JB’s recommendations (i.e. Massive Eating and Don’t Diet) are so unique: they simply apply the same general principles, albeit for drastically different goals.

That said, you’ve got a couple flaws in your line of logic (i.e. pro vs. con) for low-carb diets:

Actually, with low-carb diets, the opposite is true! Just ask anyone who tried a ketogenic diet how they responded to carbs when they came off the diet. Insulin sensitivity is reduced on such a carb-restricted plan.

This is not restricted to low-carb diets. As a matter of fact, given the same macronutrient breakdown and a higher caloric intake (i.e. isoenergetic), individuals will probably actually feel better with a lower carb approach. This all has to do with more stable blood glucose, insulin and serotonin levels. It’s the fact that one is in caloric restriction that makes you feel like you just got trampled on.

Similar to the above point, I argue that this is true of any nutritional scheme that provides less than adequate energy. It’s simply a consequence of the circumstances.

Squatman and Timbo:
I read somewhere that since you take carbs out of the equation (or lower it), and your muscle cells aren’t bombarded with carbs/insulin and thus it becomes more insulin sensitive?

First of all, how do you quote in white (yes, what is the HTML code)?

“I still follow the same train of thought as JB on this particular issue”
I take that to mean you think a higher carb approach is better?

While looking for the definition of “isoenergetic”, I came accross this study which I thought was interesting:

The effect on adipose tissue blood flow of isoenergetic meals containing different amounts and types of fat.

Summers LK, Callow J, Samra JS, Macdonald IA, Matthews DR, Frayn KN.

Oxford Centre for Diabetes, Endocrinology and Metabolism, Nuffield Department of Clinical Medicine, Radcliffe Infirmary, Oxford, UK.

OBJECTIVE: To investigate the factors regulating the increase in adipose tissue blood flow following meals. DESIGN: Eight subjects were fed three isoenergetic meals; two high-fat meals rich in either saturated or polyunsaturated fatty acids and one low-fat, high-carbohydrate meal. MEASUREMENTS: Blood samples were taken and adipose tissue blood flow was measured before and for 6 h after the meal. Plasma glucose, insulin, non-esterified fatty acid, total and chylomicron-triacylglycerol and catecholamine concentrations were measured. RESULTS: Adipose tissue blood flow rose to a peak after all three meals (P<0.05 for each). The three meals stimulated adipose tissue blood flow at similar times. There was a marked and statistically significant similarity in the time course of changes in blood flow and insulin concentrations. In contrast, noradrenaline concentrations peaked later than adipose tissue blood flow (P=0.014).

CONCLUSION: Adipose tissue blood flow may be ‘carbohydrate-stimulated’ rather than ‘fat-stimulated’, with insulin having a vasodilatory role in adipose tissue as in skeletal muscle.

That being said, I still don’t know what you meant by
“given the same macronutrient breakdown and a higher caloric intake (i.e. isoenergetic”)


A7, do you happen to be a relative to A1 Steak Sauce? Just joshing you, bro:-)

Okay, I’ve seen the data that you read on enhanced insulin sensitivity with low-carb/no-carb diets. First of all, the study (that I read) involved big-time fatties. Second of all, the determination of insulin sensitivity was completely flawed. Let me explain.

Insulin sensitivity refers to a lesser amount of insulin secreted for a given amount of carbohydrate.

That said, the researchers baseline data was taken in the obese women before the low-carb diet. Hyperinsulinemia (i.e. chronic high insulins) is a characteristic of the obese population. The researchers compared the baseline data to another measure of insulin like twelve weeks after the initiating the low-carb diet. Rather than feed the subjects a carbohydrate meal, they simply measured resting insulin levels as a function of the current (low-carb) diet. Of course insulin will be lower! There were no carbs! The researchers went on to conclude that this was an indicator of insulin sensitivity. How the hell that got published beats the hell out of me.

My comments about the higher carb protocol simply revolve around the fact that I feel it’s a long-term approach that one can live with at all times. I find it much more difficult that one can follow the low to no-carb diet forever. That’s all I was implying; not necessarily that it was better. As a matter of fact, I won’t hesistate to surmise that the low-carb approach is more efficient for short-term weight loss.

I apologize for the confusion with the isoenergetic term. That was flawed. Isoenergetic refers to equal proportions of macronutrients, and that’s not what I meant.

What I meant was that given the same macronutrient intake (i.e. low-carb, moderate fat, high protein) and a maintenance level intake (that’s what I meant by iso), I feel that most individuals will actually feel better than a high-carb approach with the same amount of kcals. This is due to the reasons I mentioned (i.e. stable blood glucose, insulin and serotonin levels).


A1 is the sauce but I’m the beef :wink:

OK, so insulin sensitivity is out.

So I guess the ONLY advantage of a low-to-no-carb diet is “more efficient”?

(and of course “feeling better” but personally I feel better on a higher carb diet).

And what about muscle loss? Would you lose less muscle on a moderate-carb diet than a low-to-no-carb diet?

Mr. Steak, this is something that you might personally have to test the waters on yourself. First off, I have no dieting experience; secondly, this may be an individual thing. Others’ opinions and experiences would be far more valuable than my own in this instance.

Thanks Timbizzo.

Theoretically (and I know you are the expert in this field), would you lose less muscle on a low-carb diet or a low-fat diet given the calories and protein being equal?

Carne Asada Steak…Great Question! I strongly feel that the most muscle-sparing, fat-burning approach would be one in which a low-carb approach is taken during all times outside of the few hours after training.

When I say low-carb, though, I’m not saying strict keto. I’m referring more to protein and fat combos like JB would advocate. That is, high-protein, plenty of good fats and a decent dose of fibrous veggies.

Immediately post-training (and perhaps during training), carbs and protein should be ingested in liquid form. Another protein and carb meal should be eaten after the liquid meal or training.

Then one should resume low-carb feeding with protein and fat meals.

People who use a Zone approach inititally see a decrease in insulin produced by a meal (probably secondary to decreased carb intake), but then insulin release for meals adjusts upward to equal earlier levels. It’s POSSIBLE that alternating different periods of daily carb intake might be beneficial for insulin sensitivity and body composition. Correlation does not equal causation, but the diet in the book SLICED was very successful for some people. It used a mid-GI source of carbs with a very-low-GI source and then scratched the mid-GI source for a spell.