Time to get even fatter. At least intellectually. A comment I made in a recent article apparently set a pea beneath the many mattresses upon which TC sleeps. It had to do with how dietary fats enhance the insulin response to carbohydrates. To put it succinctly, TC couldn't help but notice it and figured readers would too. They did. Should fat be eaten with carbs or not?

JB: Before we delve into this discussion, I'd like to make a few comments to set the stage for what we should strive to accomplish in this roundtable. First, it's exceptionally easy to get lost in theoretical discussions, to dissect any particular phenomenon (physiological or otherwise) in order to gain some new insight while at the same time losing the appropriate vantage point from which we can apply the new information.

To this end, I think it's important to note that while discussions about responses to individual meals are interesting and useful, at the end of the day, each of us has to come up with an appropriate plan for ingesting the specific amount of protein, carbohydrate, and fat required to achieve our desired goals. After all, the reason we discuss the theoretical rationale behind meal combinations or meal timing is so that we can use this information to develop a functional plan. So in discussing specific meal combinations let's not forget that at the end of the day, each of us has to consume enough protein, carbohydrates, fats, and total energy to assist in the attainment of our goals.

LL: Definitely. There are multitudes of "diets" out there, most based on a singular, clever idea. But at the end of the day, it's still total daily kcal and macronutrient intake that matter greatly to the aspiring athlete. It's prudent to remind everyone that protein intake is typically held steady (e.g. at a gram per pound) while carbohydrates and fats are the energy sources. Whether an individual prefers one or the other – or a specific combination – is of secondary concern.

TC: Sure, I "grok" all that, but let me quickly explain that I'm not really a 40-30-30 guy. I think one-size fits all macronutrient prescriptions are odious. I'm actually of the mind that we humans can get by with far fewer grams of carbs than is generally believed. After all, we need protein to live, we need fat to live, but take away our carbs and all we get is a little grumpy.

With that said, I think avoiding all carbs is unrealistic, especially for bodybuilders and endurance athletes. In the case of bodybuilders who are trying to bulk up, getting all your calories from just protein and fat can be problematic in a whole bunch of ways. Likewise, the endurance athlete would do well to have a nice store of glycogen warehoused in his muscles so that he doesn't collapse after the first 10 kilometers in his "Greater Urbana Ectomorph 15 K Fun Run."

But I digress. Back to the question. Are carb and fat combinations good or evil? Generally speaking, in my humble opinion, they're definitely not evil. Let's go back in history a bit. During the early 17th century, a high-grinding system of milling was introduced that resulted in very fine white flours. These flours pretty much replaced the coarser stone-ground flours. As such, the actual particle size, in addition to the inherent fiber content of these grains, decreased. That meant that the body could absorb them incredibly quickly (given that the digestive system wasn't left with much to do) which lead to dramatic surges in blood sugar and insulin. Lo and behold it was about this time that obesity and its partner in crime, diabetes mellitus started to show up.

However, about 80 years ago, a researcher named Jacobsen noticed that eating bread with butter produced a much smaller rise in blood-glucose concentration than did bread alone. Subsequent research has confirmed Jacobsens' observations again and again. Fat, when added to a carb meal, impairs gastric emptying as well as absorption of the carbohydrate. The fat both increases the viscosity of the sludge in your stomach and interferes with the enzyme carbohydrate interaction.

I've also done tons of informal experiments to confirm aspects of this. All it takes is a timer, a nifty little drug store glucometer, and a manly disregard of the pain caused by finger pricks. What I'd done is eat plain carbs and tested by blood sugar every 15 minutes of at least an hour. Then, I'd test that same carb source, only this time, ingest it with a little fat, usually in the form of oil, peanut butter, or even whole milk. Without fail, the carb-only foods would send blood sugar skyrocketing, with a concurrent blood sugar crash (below baseline) an hour later. Interestingly, you know what the worst food I tested was? Special K cereal, the dieter's alleged dream.

Given that most of the carbs we eat in modern society are highly processed, it seems prudent to eat fat at the same time to dull the blood sugar and subsequent insulin rise. In fact, eating fish oil with a carb seems like it would be the smartest thing to do, given that omega-3 unsaturated fatty acids seem to have an ameliorating effect on glucose tolerance. Who knows? It might have something to do with increasing sensitivity to insulin at the cell level. Likewise, eating a carb with a protein would also be prudent, as that, too, would slow down absorption and ameliorate the insulin response.

By the way, this doesn't directly pertain to the question, but it seems, too, that adding vinegar or some fermented vegetables to your carbs also reduces the rate at which starch is digested. The same goes for sourdough-type breads. Anyone for a pickle on sourdough sandwich?

LL: Thanks for the history, TC. We need to be reminded of the social and technological events leading to America's current state lest we slip into pointlessly academic banter based on the latest single study. And now I'm faced with my own smarty pants question... Hmm. Carbs with fats... Was Dr. Jekyll good or evil? With regard to this point, I think he'd be a benevolent friend to thin, more ectomorphic guys but a malevolent fiend toward thicker-skinned endomorphs. What the heck am I talking about? Well, either I'm watching too many old horror flicks or I'm saying that carbohydrate + fat combinations may be helpful to those who wish to maintain higher insulin – and glucose – levels for a long time – such as thin, highly active guys – while those trying to shed body fat should probably avoid the combo. Oh yeah, and just to be disagreeable, John, you putz... you're, uh, dressed badly today.

CW:: Well, being as it's been shown that simply slowing the rate at which glucose enters the bloodstream or (intestinal glucose absorption rate), I'd simply suggest that you make sure a higher amount of fiber is contained in each meal. Back when guar gum was used, they'd demonstrated increased insulin sensitivity simply because of its effect on slowing/reducing absorption of glucose and it's thought to be one of the mechanisms of action with metformin.

Now where I think people screw this up is by saying "Okay then, fat-free cookies and some Metamucil." No, what they should be thinking is "Okay, a chicken breast and some oatmeal" or just simply "oatmeal." Aside from that, you should be eating things that are harder in texture, high in fiber, consuming protein, casein (smiling) when possible and yes, it's okay to add some fish oil caps in there as well.

However, if you're simply using the fat content to slow absorption of glucose, then why not use something that doesn't have any caloric value, like fiber? So, no, unless you're one of those skinny guys that Lonnie mentioned, avoid fat and carb containing meals and stick to meals that are high in fiber. Remember, the lower the amount of glucose in the bloodstream, the less insulin will be secreted and the easier it will be for those adipocytes to release those nasty droplets of fat. Now if you're one of those skinny bast...err I mean individuals, then as Lonnie pointed out, you can certainly benefit from having consistently high insulin levels. Actually that's the entire premise behind my "Skinny Bastard" diet.

JB: Gasp! Combining carbohydrates and fats in a single meal is a dietary strategy straight out of the fiery inferno, introduced by ol' Lucifer himself and enforced by his evil minions! Well, at least that's what some of my Massive Eating archangels might have you believe. Being their Massive Master, though, it's important that I tighten the reins a bit. Therefore I'm glad you asked this question, Lon Solo.

Ever since my Massive Eating articles and the introduction of my Don't Diet plan, many readers have misinterpreted the recommendations to mean that a carbohydrate containing meal must never contain so much as a single gram of fat while a fat containing meal must never contain so much as a single gram of carbohydrate. This is unfortunate since my specific comments stated that:

In these statements, the key words here are obviously underlined. Basically my point was that when one of the two macronutrients was consumed in high quantities, the other must be consumed in low quantities. My generalized and rough guideline has been that any high-carb meal should contain less than 10g of fat while any high fat meal should contain less than 15g of carbohydrates. And of course, protein should be consumed with every meal. These recommendations are designed for those weight trainers interested first and foremost in body composition alterations.

LL: ...bringing us back to the ol' "hold protein steady and choose your energy source" idea...

JB: As described in both my Massive Eating and Don't Diet plans, one of the reasons why we try to minimize this potentially fattening combo of high fat and high carbohydrate meals is because of the very same synergistic insulin release that has been described above. In 1996, when Dr. Holt and colleagues were formulating those famous insulin index charts, they noticed that foods containing refined carbohydrates and fats seemed to generate a disproportionate insulin response relative to the actual carbohydrate content as well as the glycemic index of the meal. This indicated that meals high in fat and carbohydrate could promote a nasty case of hyperinsulinemia.

This is the very same hyperinsulinemia that prevents the mobilization of fats from the storage depots of the adipose tissue to the metabolic furnaces of the muscle where they can be burned for energy; the very same hyperinsulinemia that, when combined with high blood levels of fat, can cause uptake of both fat and carbohydrate into the adipose tissue for fat building.

Numerous studies over the years have supported the notion that fats indeed may enhance the insulin response to carbohydrate ingestion and that hyperinsulinemia both shuts down fat burning and enhances fat building, especially in the presence of hyperlipidemia. In 1998, Holtschlag et al discussed the possibility that ingested fat also may potentiate the amounts of insulin stimulated by ingested carbohydrates. The effect of these ingested nutrients (fats, proteins and carbohydrates) on insulin secretion is direct, through stimulation of insulin secretion – via glucose and absorbed amino acids – and is indirect, through stimulation of hormone secretion, via ingested proteins, carbohydrates, and fats.

While the Massive Eating/Don't Diet plans aren't perfect (no human attempt at manipulating physiology is), I believe they provide a functional way to consume an abundant amount of micronutrient dense, glycogen-replenishing carbohydrates and metabolism altering, hormone-stimulating fats, and muscle-building proteins while simultaneously preventing excessive hyperinsulinemia and excessive fat gain.

After all, high blood levels of insulin, carbohydrates, and fats (due to the synergistic insulin secretion promoted by a carbohydrate + protein + fat meal as well as the absorption of these nutrients) can lead to more nutrients being shuttled to your fat cells than desired. Why not try to minimize this potentially enlarging combination? One of the most logical ways to do this while ensuring you get all the nutrients you need is to combine your meals properly.

LL: Okay, everybody take a deep breath... he's still talking...

JB: So where's the scientific data? We don't got none. But the theory makes some sense. However, theory aside, thousands of weight lifters and strength athletes have benefited from these recommendations, reporting exactly what I had indicated in my first Massive Eating article; they simply can eat more calories than they ever thought possible without gaining as much fat as they might have expected. In other words, the proportion of lean mass gained to fat mass gained is improved (if trying to get bigger) and the proportion of lean mass retained to fat mass lost is also improved (if trying to get leaner). Of course, other programs can also produce results. But from what I've seen of these recommendations, this plan is one of the better ones.

Before we move on, though, I want to pacify the science savvy out there. I've simplified matters here for explanatory purposes only, since nutritional science is wrought with great complexity. One example of this is the fact that insulin is not the only regulator of fat storage. Adipose tissue can be stuffed full of fats and carbohydrates in an insulin independent manner via a hormone called "ASP" or Acylation Stimulating Protein. This hormone doesn't need insulin to make you fatter. Rather, it's released from fat cells directly in response to blood chylomicrons (pre-packaged fats) and is responsible for increased triglyceride synthesis in the adipose cells. Basically, ASP works for fat storage like insulin works for carbohydrate storage.

So, does this mean that the Massive Eating/Don't Diet combos will not work since fat can be stored even without high blood levels of insulin? Heck no! All it means is that there are all sorts of physiological phenomenon occurring that we either don't understand all that well or don't even know about. But rather than throwing our hands up in resignation, we should focus on what we do know in order to manipulate what we can. In this case, by using our diet to manipulate insulin concentrations, we can favorably affect body composition. I'd love to talk all day on this topic, but for now, I think a few of the other guys might like to get a word in edgewise.

TC: Damn straight! I don't disagree that you shouldn't ingest high amounts of carbs and high amounts of fats in one meal. However, I think it's a bit unrealistic to go through life – you know, eating out, going to your girlfriend's house for dinner, etc. – and have to grab the waiter and/or potential future mother-in-law by the neck and slam their head into the wall every time they have the temerity to combine fats and carbs. I know, I know, as bodybuilders we're not ever supposed to "slip up," but hell, I'm talking all things in moderation, here. When presented with a menu or meal that doesn't come from the kitchen of the bodybuilding gods, practice damage control and combine high GI carbs with fats and/or proteins.

And as far as John's Massive Eating plan, I admire the hell out of it for its elegance and intellectual thinking behind it, but unless I'm mistaken, most diets where you grossly overeat end up adding about 70% lean mass and about 30% fat mass. That's why tubby guys aren't generally as tubby as we think they are. There's usually a lot of muscle underneath that lard.

TC: Sure, I wouldn't combine fats with carbs in the much-hallowed post workout period. As badly dressed John Berardi has pointed out time and time again, this period, in particular, is when you want to sledgehammer your insulin rate sky high. Likewise, in general, I don't think eating carbs by themselves is a bad thing for the ectomorph who desperately wants to put on weight – any kind of weight. However, my only fear is that this individual, might, in the long run, create some insulin resistance and find it ultimately a little harder to shed some of his newly acquired lard.

JB: As stated above, my basic low carb with higher-fat meals and low fat with higher carb meals are designed – first and foremost – for weight trainers interested in body composition change. You know – emaciated guys like Lonnie, TC, and Cy.

If you're a competitive athlete and your primary goals are performance and recovery, then you have some special concerns that these basic rules do not address. For example, major concerns of athletes include steady energy provision (carbohydrate 2-3 hours before training or competition as well as during competition) and glycogen recovery (abundant post exercise carbohydrate intake). Since carbs are such a large part of the competitive athlete's day, fats and proteins often have to be included in higher carb meals. Does this mean athletes are destined to balloon up like male spider monkeys during mating season? Nope. If you're training correctly as an athlete, your body is probably quite opposed to fat storage anyway and the "devil's combinations" will probably not wreak havoc on your adipose content.

Another exception concerns the type of carbohydrate. Meals that contain protein, fat and very low glycemic index/insulin index carbohydrates that are also fibrous may also be okay. Therefore it seems that foods like beans, nuts, vegetables, and some fruits appear to be "rule breakers." Due to their low GI and II characteristics, these foods generate very little insulin response and don't dump glucose into the blood at a substantial rate. This means that they won't create the dreaded high insulin, carbohydrate, and fat concentrations in the blood. Since they are also often rich in vitamins, minerals, and healthy fiber, they are certainly an acceptable addition to a protein and fat meal – in moderation, of course, with the "bulk" of these types of foods being served during your protein + carb meals.

Finally, while meal combination rules have been very effective for many trainees trying to promote a gradual weight loss, they appear to especially shine when applied to those trying to gain muscle mass (i.e. Massive Eating) while minimizing body fat. While Lonman makes a good theoretical point in suggesting that perhaps chronic hyperinsulinemia may be the kick start that some skinny bastards need to gain mass, I will continue to assert that the Massive Eating plan appears to be the best way to accomplish what most weight lifters really want – low-fat beef, baby.

LL: You betcha, JB; TC has mentioned that too. Screaming insulin concentrations over weeks and weeks could eventually become counterproductive due to retarded insulin sensitivity (a la type II diabetes). I like the term "kick start," though.

Time of day is also a big confounding factor regarding fat and carb "rules." I personally try to avoid fat + carb combinations in the morning (or fats, period). There are data out there suggesting that glucose tolerance is impaired with a fatty breakfast. I wouldn't want to seriously mess up my glucose tolerance for five or six hours when it's otherwise at its best. A big mid-morning carb snack or lunch isn't doing a lot of good if one's muscles are resistant to accepting the resulting blood glucose.

I've mentioned before that fat may be a better choice in the evening – but in place of carbs. There is actually research likening healthy nighttime carb-eating subjects to diabetics! "Carb handling" actually gets that bad. I guess here is where my interpretations jive with JB's. Protein with whole-grain carbohydrates in the morning, protein with fat in the evening is logical for most folks. Although, again, skinny guys may want to keep the carbs, fats and proteins flowing pretty much all day. There is insulinogenic synergy here. Maintaining higher insulin concentrations around the clock is the anabolic sledgehammer that they may need to grow.

CW:: Damn it Lonnie, now what the hell am I supposed to say? Well, I have to completely agree with what Lonnie said and don't have much to add. Well, one thing I should mention is that even for those individuals who have a more difficult time reducing fat stores, they too should still have one liquid, whey-containing, fiber-free, glucose or dextrose-containing meal and that would be after their workout.

TC: I can't argue with any of that, either.

JB: I mostly agree with LL's comments here, too. While the meal combination rules still stick, it's crucial to recognize that another issue, nutrient timing, is also important when considering when certain meals (P+C or P+F) should be consumed. I agree with Lonman's morning and nighttime recommendations and will go one step further in reiterating that 90-120 minutes before training a P+F meal may be the best suggestion, while after training, P+C meals are essential.

TC: I wouldn't think it would have any cons, except that, again, in the post-workout period, it might slow down the rate at which amino acids enter into the bloodstream and end up in target muscle cells. I also don't mind protein-only meals. While it's true that protein itself causes an insulin response, it also stimulates glucagon release, in contrast with carb-only meals that cause insulin to increase with a concurrent decrease in glucagon.

In other words, were it not for this protein-induced release of glucagon, the protein-induced release of insulin would lead to a hypoglycemic state. What happens is that the glucagon induces breakdown of hepatic glycogen to "cover" the insulin release.

JB: Most practically, since my plan suggests very little fat with P+C meals, it's obvious that the daily dietary fat intake has to either be provided as a fat-only meal or in conjunction with protein as a P+F meal. The importance of a good amount of fat, especially healthy fat, has been discussed repeatedly here at T-mag so let's just assume that a good amount of dietary fat (20-30% of total kcal intake) is required and then move on. Since a fat only meal provides virtually no metabolic increase (thermic effect of feeding) as well as provides none of the daily protein requirement, I think it's important to consume protein and fat meals when not consuming protein and carb meals.

Besides the practicality of it all, meals combining protein and fat may offer other benefits. Since the inclusion of fat leads to slowed gastric emptying, adding fat to a high-protein meal may effectively slow the rate of the protein absorption, creating something analogous to a time-released protein. This would make the P+F meal ideal for bedtime snacks, especially if you choose the appropriate protein source.

Next up: Glucagon. Since glucagon is a regulatory hormone responsible for providing energy to the tissues, it is classified as a catabolic hormone. Essentially, glucagon plays Lex Luther to insulin's Superman. To be more specific, glucagon stimulates the breakdown of stored glycogen into glucose in skeletal muscle and in the liver, stimulates the breakdown of fats into fatty acids in adipose tissue, maintains the liver's output of glucose from amino acid precursors, and leads to the formation of ketone bodies from fatty-acid precursors in the liver; all catabolic events designed at dipping into your energy reserves to provide fuel.

Since a protein-only meal increases the release of glucagon (in order to stimulate the liver to produce glucose to normalize blood sugar) and since fat does nothing to directly mitigate the effects of a protein meal on glucagon release while carbohydrates decrease this response, some have speculated that a protein-only meal or a protein-plus-fat meal is a no-no since the glucagon release may promote the manufacture of glucose from all those ingested amino acids.

While this may be true with a high protein diet that also lacks sufficient dietary carbohydrate, I believe that the destruction of amino acids will be minimal if the body has sufficient carbohydrate reserves in the liver. In this case, glucagon will tend to make more of the necessary blood glucose from stored glycogen than from ingested amino acids. Sure, some of those aminos will be destroyed. But you've gotta get your fat in sometime and if you're eating enough protein in your diet, there will be plenty left to keep you growing. Besides, although fat does not necessarily mitigate the glucagon response directly, the fact that fat slows the intestinal transit of the protein indicates that over time, the glucagon response to the same protein meal will be less since there are less amino acids being absorbed per unit time to stimulate glucagon release.

TC: Alright, Berardi! Screw this academic bullshit. I challenge you to an old fashioned duel. Choose your weapon: a protein and fat combo of ham hocks or a carb and protein combo of corn dogs at thirty paces.

LL: Hey! TC, can you stop mocking the Large Professor? He's up on that soapbox again, for sure, but I'm trying to keep this civilized!

I did once see a study that fat present in protein meals helps maintain Testosterone levels post-prandially (after eating). But it goes beyond that. Slowed gastric emptying would help dole out that protein to otherwise starving muscles at night, too. I've got to think a steak before bed would maintain serum concentrations of amino acids longer than, say, whey mixed into water or juice.

CW:: Lonnie, I have to agree with that wholeheartedly as well. You know, casein is great in terms of slowing gastric emptying as well. Aside from that is the fact that when you sleep, you should enjoy lower plasma insulin levels, which would allow for increased fat oxidation. Oh, and not that this matters much, but just for fun it could result in higher GH levels while sleeping as well. Basically, you should gain 50 lbs. of lean body mass and wake up with 3% body fat when utilizing this method. Kidding!

TC: Okay, I agree with all of you there, too. Fat and protein at night would slow gastric emptying and act as a "time release" protein of sorts.