Dr. Lonnie Lowery - 5 Reasons You May Need Fewer Carbs

Dr, Lowery is one of the few nutrition gurus I listen to and respect. This is a good article on living well on fewer carbs, which is my favorite way to eat.

Dr. Lonnie Lowery - 5 Reasons You May Need Fewer Carbs

In many ways, dietary carbohydrate is the one macronutrient that's most apt to be manipulated during the year by strength athletes. Protein can be held steady effectively at around one gram per pound of body mass and research suggests dietary fat should be kept at about 85-100g daily for many men to maintain higher testosterone levels.(2, 14) But as a readily dispensable and fluctuating fuel, carbohydrate can differ. Its insulinogenic and muscle (glycogen) expanding properties make it attractive during mass building phases but there are also times of the year when fat loss becomes a goal. (Insulin stimulation is not conducive to fat loss at all.) Beyond this, there are a number of factors that influence and hamper dietary carbohydrate "handling". Some of these are modifiable (self-induced and environmental) and some are non-modifiable (genetic and age-related). Let's review them…

1. Muscle Soreness

It's not really up for debate anymore that sore and micro-traumatized muscles (from eccentric contractions, or "negatives") don't take-up blood sugar well. They have perturbations in the biochemical insulin pathways and just don't accumulate glycogen as well as "non-sore" muscles do.(3, 16, 18) Are you someone who is routinely sore, nearly from head to toe? I am.

And I wonder if, coupled with a family history of Type II diabetes, that this makes me someone who might do better on a 40-50% carbohydrate diet than the oft-recommended 60-70% carb diets promulgated by many "sports nutritionists".

I mean, if my sore and recovering muscles aren't taking-up the resulting blood sugar, where might it be going? (The liver can only store so much, typically 70-90 grams, so is triacylglycerol [fat] storage the net result?) Hence, these days I tend to consume breads and pastas as treats rather than staple foods - and know what? I find myself eating more vegetables because of it.

2. Middle Age

It has been stated that the consumption of sugars and fats are associated with the glucose intolerance seen in mid-life.(13) Indeed, reductions in "carb handling" such as impaired insulin sensitivity and beta cell function by middle-age are not unheard of by any means.

Yet aging isn't a modifiable risk factor is it? If you don't want to turn 40, tough cookies. And yet there is hope (beyond avoiding cookies). Many of us are already aware of it: Both aerobic conditioning and resistance training strongly compensate for the glucose intolerance seen during aging (even "middle-aging").(15)

Muscle contractions can maximally take up blood sugar without insulin's presence ("GLUT-4 translocation" for you nerds), blood flow goes to where it should (muscle should be receiving 70-80% of ingested carbohydrate), muscle mass is maintained and central body fat is reduced, and long term glucose tolerance is improved (except during periods of eccentric soreness). The take home message? Lift and do your cardio.

3. Family History

Researchers have documented that relatives of those with Type II diabetes are themselves poorer "carbohydrate handlers".(5, 12) This is another one of those un-modifiable risk factors. (Perhaps you should have chosen your parents more wisely?)

And so we are left correcting for a certain genomic propensity towards glucose intolerance and/or hyper-insulinemia. Fortunately, researchers have also provided some potential answers. In a famous study by Jenkins and colleagues, nibbling several small meals, as opposed to "gorging" on three big ones each day decreased insulin concentrations 28% (and cortisol 17%, a nice bonus).

This really rolls with my mantra of daily meals: "Eat it… burn it… eat it… burn it". Your body runs continuously, not intermittently, so why not consider feeding it thusly? I think it's also fascinating that soluble fibers, such as that of oat bran, slows the movement, digestion and absorption of food - much to a poor "carb handler's" advantage. We're talking about decreasing post-meal insulin concentrations 35%, and glucose levels 50%.(17)

And before you think that you have no family history - and are thus in no need of smaller frequent meals or oats - consider this: At least 20% of the population has metabolic syndrome (a collection of insulin insensitivity and various cardiovascular risk factors). Plus, 6% of college students are in a similar boat.(7)

4. Eating Late on Non-exercise Days

The tenets of "Temporal Nutrition" are based in part on the premise that even healthy persons' glucose tolerance is not very good at night.(4, 10, 19) Have you ever heard of the nurse's health study in which nighttime eaters gained more weight and fat than similarly-eating daytime counterparts? It's still further support of this temporal concept in my opinion.

But what to do? We can't stop the daily clock!

Well, as noted above under the "Middle-age" heading, exercise is a great modulator of glucose metabolism- and it helps on those evenings of the week when we are actually in the gym. But who can - or would want to - work out seven days per week?

I suggest that, if you feel a carb reduction (of say 10%) in your daily diet is warranted, you first consider removing bread and pasta from your "off day" dinners (perhaps 2-3 nights each week). As I said above, you may find yourself eating more veg - thus improving overall diet quality - because of this simple change.

5. Dieting Phases

As a nutritional biochemisty professor, I see a real trend in many textbooks (check out the paperback, Biochemistry Primer for Exercise Science by Mike Houston as a good start) that supports potential problems with chronically high carbohydrate diets (and their accompanying hyper-insulinemia). These diets induce gene changes over time that produce lipogenic ("fat building") enzymes in the body.

You see, not long after learning that insulin is a hormone that "pushes sugar out of the bloodstream and into tissues", an avid student learns that it's a storage hormone that is also strongly involved in triacylglycerol (fat) storage. It simultaneously inhibits the biochemical "fat breakdown machinery" in cells.

Overall these are good things, maintaining body weight and keeping us from being diabetic. Trust me, you don't ant to rapidly and seriously lose huge amounts of both muscle and fat in the way an uncontrolled Type I diabetic person does.

Nonetheless, for the "dieter", reducing carbohydrate can be a primary tool in reducing body fat. This can be as simple as not drinking sugary carbs with meals (1), keeping carbs out of the "fat burning" pre-cardio period (11), switching to higher fiber foods such as oat bran over oatmeal, or removing bread and pasta from meals a few nights each week.

Since protein needs will be maintained or increased as one diets, and going to a super low-fat diet can have the aforementioned hormonal consequences, this is a sane approach to "nutritional periodization".

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Hopefully this little exploration of the scientific literature and the practical aspects of carbohydrates was helpful. Of course, for those enduring frequent and long bouts of training, keeping carbohydrate intake up is important to fight fatigue, overtraining, muscle "flatness" and other reasons. But for those readers who experience a collection of this article's five cautionary factors, the potential solutions herein may be just the ticket.

References / Further Reading:

1.	DiMeglio DP, Mattes RD. (2000). Liquid versus solid carbohydrate: effects on food intake and body weight. Int J Obes Relat Metab Disord. Jun;24(6):794-800.
2.	Dorgan, J., et al. (1996). Effects of dietary fat and fiber on plasma and urine androgens and estrogens in men: a controlled feeding study. Am J Clin Nutr 64(6): 850-855.
3.	Doyle, J., et al. (1993). Effects of eccentric and concentric exercise on muscle glycogen replenishment. J Appl Physiol 74(4): 1848-1855.
4.	Grabner, W., et al. (1975). Diurnal variation of glucose tolerance and insulin secretion in man. Klin Wochenschr Aug 15;53(16):773-8.
5.	Han, X., et al. Insulin sensitivity and beta function in the first-degree relatives of type 2 diabetic patients. Zhonghua Yi Xue Za Zhi. 2004 Nov 2;84(21):1777-80.
6.	Houston, M. (2006). Biochemistry Primer for Exercise Science. Human Kinetics Publishers: Champaign, Illinois.
7.	Huang, T., et al. (2004). Overweight and Components of the Metabolic Syndrome in College Students. Diabetes Care 27:3000-3001.
8.	Jenkins, D., et al. (1989). Nibbling versus gorging: metabolic advantages of increased meal frequency. N Engl J Med Oct 5;321(14):929-34.
9.	Layman, D., et al. (2003). A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women. J Nutr 133(2): 411-417.
10.	Lee, A., et al. (1992). Diurnal variation in glucose tolerance. Cyclic suppression of insulin action and insulin secretion in normal-weight but not obese subjects. Diabetes 41(6): 742-749.
11.	Mick, T., et al. (2002). Comparison of sports drinks on substrate oxidation during exercise. (Abstr) CCF Dept Orthopaed Surg 12th Ann Res Day, Cleveland, Ohio.
12.	Perseghin G., et al. (1997). Metabolic defects in lean nondiabetic offspring of NIDDM parents: a cross-sectional study. Diabetes. Jun;46(6):1001-9.
13.	Preuss, H. (1997). Effects of glucose/insulin perturbations on aging and chronic disorders of aging: the evidence. J Am Coll Nutr Oct;16(5):397-403.
14.	Reed, M., et al. (1987). Dietary Lipids: An additional regulator of plasma levels of sex hormone binding globulin. J Clin Endocrinol Metab 64(5):1083-1085.
15.	Ryan, A. Insulin resistance with aging: effects of diet and exercise. Sports Med. 2000 Nov;30(5):327-46.
16.	Sherman, W. (1992). Effects of downhill running on the responses to an oral glucose challenge. Int J Sport Nutr 2(3): 251-259.
17.	Tappy, L. et al. (1996). Effects of breakfast cereals containing various amounts of beta-glucan fibers on plasma glucose and insulin responses in NIDDM subjects. Diabetes Care. Aug;19(8):831-4.
18.	Widrick, J., et al. (1992). Time course of glycogen accumulation after eccentric exercise. J Appl Physiol 72(5):1999-2004.
19.	Wu, M., et al. (1986). Diurnal variation of insulin clearance and sensitivity n normal man. Prc Natl Sci Counc Repub China B 10(1): 64-69.

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