Drew Baye’s High Intensity Training

In a previous post I wrote about the ten biggest bodybuilding mistakes, I listed not training hard enough as the number one mistake. How hard is enough, though?

To stimulate increases in strength and size it is minimally necessary to 1. work your muscles harder than they are accustomed to, which means 2. always attempting to lift a few more pounds or perform a few more repetitions on each exercise than you did before. These are the two most fundamental principles of building muscular strength and size – overload and progression. If these two things are not the primary focus of your training, nothing else you do is going to make any difference.

Weighted Dips

To stimulate the greatest possible increases in strength and size it is necessary to work as hard as possible. Do not make the common mistake of confusing doing more exercise for working harder. Working harder means putting more effort into each exercise, and if your level of effort is high enough you will neither need nor be capable of performing a large volume of work.

To work as hard as possible simply means;

1. doing as many repetitions as you are physically capable of
2. in reasonably good form
3. with an adequately heavy weight

Physical Versus Psychological Limits

Most people quit an exercise for various psychological reasons long before they’ve reached their true physical limits. Beginners and others unaccustomed to training at a very high level of intensity often mistake a moderate level of fatigue for muscle failure, quitting when the exercise starts to get hard rather than when more reps become impossible. Many simply quit when the exercise becomes too uncomfortable for them, lacking the necessary mental toughness to push through the discomfort of burning muscles, a rapidly pounding heart and being out of breath. Some quit when an exercise becomes harder because they fear they will injure themselves.

The gap between psychological and physical limits narrows and the tolerance for muscular burning and exertional discomfort improves for most people after they’ve been training for a while, but even advanced trainees may quit far short of a true all-out effort if they’ve never experienced it. Even many advanced trainees overestimate how intensely they actually train and underestimate the level of effort they are capable of. A good solution for this is to work out with a trainer or partner that knows how to motivate you to go all-out. The judicious application of high intensity training techniques like forced reps and negatives can also help you develop the ability to push yourself harder during training.

If you quit an exercise when it gets harder due to fear of injury, consider it is not the amount of weight or how hard you are working but the integrity of your form that determines your risk of injury. As long as you maintain reasonably good form and use a competent and attentive spotter or the appropriate safety equipment when necessary there is no reason to fear injury.

Also consider no matter how fatigued you become, you are always much stronger holding or lowering a weight than you are lifting it. As long as you don’t just let go, you will not drop a weight on yourself.

Good Form

The goal of an exercise is not to make a weight go up and down. Lifting and lowering a weight (or just lowering, if you’re doing negative-only reps) is just a means to accomplish the real goal, which is to work the targeted muscles intensely enough to stimulate strength and size increases. To accomplish this you need to maintain the proper body position and move along the correct path over the correct range of motion to maintain a high level of tension on the target muscles while avoiding positions which may result in other tissues being exposed to potentially harmful levels of force.

As an exercise becomes harder do not significantly alter your body position or path or range of movement or attempt to yank, jerk or otherwise quickly move the weight to make it easier to lift. If you do, the work is either shifted away from the target muscles towards other muscles or leverage is changed reducing tension, and you are no longer accomplishing the real goal, or you increase the risk of injury due to the sudden, uncontrolled increase in force resulting from rapid acceleration. It is neither necessary nor beneficial and potentially dangerous to attempt to continue beyond the point where can not lift the weight in correct form by cheating.

Maintain your focus on the real goal – high intensity muscular work – and don’t sacrifice form and risk injury for the sake of a few more less productive reps. How you lift the weight is far more important than how many times.

How Heavy?

The weight should be at least heavy enough to be moderately hard to lift right from the start. It should not be so heavy, however, that you are unable to perform at least a few repetitions in good form.

Assuming a moderate movement speed, within reason repetition range doesn’t appear to make as much of a difference in muscular strength and size increases as the effort put into an exercise. Some people will find they do better with or prefer slightly higher or lower reps, however most people will get good results with any reasonable range from as low as three to as high as twenty, as long as they are working as hard and progressively.

I recommend a middle range of 7 to 10 repetitions as a starting point for most trainees and most exercises. A higher rep range may be more appropriate for beginners when learning a new exercise, and lower rep ranges may be more appropriate if using very high intensity training methods like rest-pause or negative-only.

The High Intensity Mindset

High intensity training is as much a test of mental toughness as it is of physical strength, and your mindset going into the workout has a big impact on how hard you’ll be able to train. I have found the following to be effective in establishing the proper mindset for going all-out during your workouts.

Commitment

Although you may enjoy the mental and physical challenge of a hard workout, a workout is not an end in itself, but a means to accomplishing specific goals. Keeping your goals in mind will help you stay motivated. Think about how important those goals are to you and make a commitment to yourself to give your best effort, to not have any doubts after the workout as to whether you could have gotten another rep on an exercise or worked even just a little harder.

Focus

To put a 100% physical effort into an exercise you have to focus 100% of your mind on it. To prevent your mind from wandering or the things going on around you from distracting you during your workout, take a few minutes before you start to clear your head and get focused. Sit down, close your eyes and focus only your breathing until you are able to block everything else out and your mind is not wandering. Then take a few minutes to visualize yourself performing each of the exercises in your workout perfectly, easily beating your previous weight or reps on all of them. Finally, take a brief moment to think about your goals, your motivation for training.

Before each exercise, take a few seconds to close your eyes and regain your focus if you start to feel distracted.

Putting “Pain” in Perspective

Intense burning in the muscles, a rapid heart rate and labored breathing are normal sensations resulting from high intensity muscular work, and not real pain or an indication of physical harm. These sensations are not a cause for concern. What they do indicate is that you have reached the most productive part of the exercise.

When you begin to experience these sensations do not assume you are approaching your physical limits or the end of the exercise. Remind yourself the sensations are temporary and harmless, and the real exercise is just beginning. The burn in your muscles is your cue to work even harder, and the more they burn the harder you will work. Again, think about your goals and remind yourself they are worth working through the temporary and harmless discomfort.

Drew Baye Training

This article is posted with the written permission of the author, Professor Eyal Lederman of CPDO Ltd. in London. Thanks to Steve Turner for making me aware of the article and to Professor Lederman for allowing me to post it here.

This is important reading for anyone involved in exercise, either professionally or for their own health and fitness, and especially for those who train individuals with or have lower back pain, as it addresses many of the myths of the current core and stability training trends.

The Myth of Core Stability

Professor Eyal Lederman

CPDO Ltd.,
15 Harberton Road,
London N19 3JS,
UK,

E-mail: cpd@cpdo.net
Tel: 0044 207 263 8551

Abstract

The principle of core stability has gained wide acceptance in training for prevention of injury and as a treatment modality for rehabilitation of various musculoskeletal conditions in particular the lower back. There has been surprising little criticism of this approach up to date. This article will re-examine the original findings and the principles of core stability and how well they fare within the wider knowledge of motor control, prevention of injury and rehabilitation of neuromuscular and musculoskeletal systems following injury.

Key words: Core stability, transverse abdominis, chronic lower back and neuromuscular rehabilitation

Introduction

Core stability (CS) arrived in the latter part of the 1990’s. It was largely derived from studies that demonstrated a change in onset timing of the trunk muscles in back injury and chronic lower back pain (CLBP) patients [1, 2]. The research in trunk control has been an important contribution to the understanding of neuromuscular reorganisation in back pain and injury. As long as four decades ago it was shown that motor strategies change in injury and pain [3]. The CS studies confirmed that such changes take place in the trunk muscles of patients who suffer from back injury and pain.

However, these findings combined with general beliefs about the importance of abdominal muscles for a strong back and influences from Pilates have promoted several assumptions prevalent in CS training:

1. That certain muscles are more important for stabilisation of the spine, in particular transverses abdominis (TrA).
2. That weak abdominal muscles lead to back pain
3. That strengthening abdominal or trunk muscles can reduce back pain
4. That there is a unique group of “core” muscles working independently of other trunk muscles
5. That a strong core will prevent injury.
6. That there is a relationship between stability and back pain

As a consequence of these assumptions, a whole industry grew out of these studies with gyms and clinics worldwide teaching the “tummy tuck” and trunk bracing exercise to athletes for prevention of injury and to patients as a cure for lower back pain [4, 5]. At that point core stability became a cult and TrA its mantra.

In this article some of these basic assumption will be re-examined. In particular, it will examine:

1. The role of TrA as a stabiliser and relation to back pain: is TrA that important for stabilisation?
2. The TrA timing issue: what are the timing differences between asymptomatic individuals and patients with LBP? Can timing change by CS exercise?
3. Abdominal muscle strength: what is the normal strength needed for daily activity? Can CS exercise affect strength?
4. Single muscle activation: can single muscle be selected? Does it have any functional meaning during movement? Read more…

Drew Baye Training

If you’re not making regular gains in muscular strength and size you’re probably making one or more of the following common training mistakes. These are some of the biggest mistakes a bodybuilder can make, and correcting them can often make the difference between outstanding gains and none at all.

1. Not Training Hard Enough

To stimulate muscular strength and size increases, you have to work your muscles harder than they are accustomed to, the harder the better. Specifically, you should perform each exercise until it is impossible to continue in good form, using a heavy enough weight that you are only able to perform between 5 and 15 slow, controlled reps (some people get better results with lower rep ranges, e.g. 5-8, some with highter, e.g. 10 to 15, but most would do best to start in the 7 to 10 range and adjust from there).

The exercise is not over when the muscles start to burn or when things start to become uncomfortable. The real valuable work is just starting. The exercise isn’t even over when your muscles feel like they’re on fire and your heart is pounding through your chest, you’re just getting to the best part. The greatest stimulus for muscular strength and size increases occur during the last few hardest reps, and if you give up at any point short of an all-out effort, you aren’t going to get nearly the growth stimulation.

2. Not Training Progressively

As you become stronger you must attempt to lift progressively heavier weights to stimulate further improvement. If you continue to use the same weights on all your exercises despite increasing in strength, the weights will no longer be challenging enough to stimulate further improvements. Attempt to either perform more repetitions or use a slightly heavier weight on every exercise, every time you train.

3. Doing Too Many Exercises and Sets

It is the intensity of muscular work that stimulates strength and size increases, not the volume. Doing any more exercise than minimally necessary will reduce rather than improve gains, by interfering with the process of recovery and adaptation.

In most cases, all you need is one hard set of only one or two exercises per major muscle group. More is rarely necessary, and usually counterproductive.

4. Training Too Frequently

The body must be allowed adequate time between workouts to fully recover and adapt, or gains will not occur. Exercise does not produce any improvements in the body, exercise can only stimulate the body to produce the improvements, if it is intense enough, or prevent the improvements from being produced, if it too much is performed, too often. The body produces the muscular strength and size increases stimulated by exercise, but only if it allowed adequate time between workouts to do so.

5. Not Keeping A Workout Journal or Progress Charts

Proper adjustment of training volume and frequency to avoid overtraining requires objective evaluation of progress. If you’re not keeping accurate records of your workouts, you can not objectively evaluate the effectiveness of your program and make the necessary changes to keep gaining or get your progress back on track.

6. Using Sloppy Form

Poor form reduces the effectiveness of an exercise and increases the likelihood of injury. While an entire book could be written on the specifics of proper exercise form, one of the most effective ways to improve exercise form in general can be summed up in two words: slow down. Moving more slowly makes it easier to maintain proper positioning and alignment, and allows for better focus on performing the exercise correctly and on intensely contracting the target muscles.

7. Switching Exercises or Routines Too Frequently

Real gains are made by consistent progress on the basic exercises over time. Changing routines too frequently prevents the body from getting past the initial, primarily neural/skill adaptation stage and into the more productive training that follows.

The belief that one must change their routines regularly to avoid plateaus because the muscles “adapt” to exercise is based on the observation that the fastest improvements in performance on an exercise routine occur over the first six to eight weeks after which it begins to slow down, and that changing the routine appears to solve this problem.

During the first several weeks performing a new exercise or routine a larger percentage of the improvements in exercise performance are due to neural or skill adaptations. After this initial period of neural adaptation, performance improvements slow down and the majority of adaptation is occurring in the muscles. This is where the real progress starts, however, and it is important to not change the routine at this point. It will be slower than during the initial six to eight weeks, but you will make progress if you properly adjust your workout volume and frequency.

Contrary to bodybuilding myth and uninformed opinion, the muscles do not stop adapting to a particular exercise, method, or routine – if there is sufficient overload a muscle will be stimulated to grow, and as long as volume and frequency are not excessive, and adequate rest and nutrition are provided, and one hasn’t already reached the limits of their potential, it will grow stronger and larger.

If you only performed a few, basic barbell exercises, covering all the major muscle groups, and trained hard and progressively you would eventually become as big and as muscular as your genetics allow. There is no need to constantly switch up angles, rep methods, or anything else.

8. Not Training Legs

Heavy leg work,  squats, deadlifts, leg presses, etc., can be brutal when done properly, and as a result many would-be bodybuilders avoid it, preferring to focus on the relatively easier upper body exercises. This is a huge mistake, as heavy leg work appears to have a beneficial effect on growth throughout the entire body, particularly squats and deadlifts.

Do not skip training legs. Doing so robs you of potential full-body size increases, and having a well developed upper body and chicken legs looks stupid.

9. Not Eating Enough Quality Food

Your body requires both material and energy to produce new muscle tissue. Often, when skinny guys complain they have a hard time gaining muscle mass, it turns out they simply aren’t eating enough food in general or protein in particular to support the growth they stimulate during their workouts. If you want to get big, you have to eat big. This doesn’t mean pigging out, but getting enough calories and protein daily to add at least a few pounds per month, but not so much your waist size or abdominal skinfold increases significantly.

Just like your workouts, you have to keep track of your eating and make adjustments based on how your body responds.

10. Wasting Money on Bogus Bodybuilding Supplements

While stopping wasting your money on supplements might not make your muscles suddenly start growing, it will stop your wallet from shrinking. There are a few supplements which have proven to be beneficial, but most provide little or no benefit. If you want to know which supplements work and which don’t, don’t read about them in the bodybuilding magazines – they make a large amount of their money selling advertising to supplement companies and are hardly unbiased sources of information on the subject. Almost everything you read in muscle magazines is bullshit. If you want reliable information on supplements or their ingredients, read the scientific journals, and even then, do so critically.

Drew Baye Training

I am in the process of finishing a few sections, editing and illustrating. Starting this week I will be posting excerpts from various chapters in the book to give people an idea of what will be covered, along with some things I wrote for the book, but decided not to include and will just be posting here.

The diet project mentioned earlier is being put on hold, as all my time and energy is being directed towards getting this book finished. Once the book is finished, if it does well, I will be cutting back my personal training schedule to enable me to focus more on my own training experiments and writing, which will include working with locals and phone clients doing mass-building and cutting programs, as well as to work on a high intensity training certification program.

I urge anybody local who is interested in participating in these experiments to contact me at drew@baye.com

In other news, I plan to participate in the American Lung Association’s Fight for Air Climb on November 14th – a timed 25-story climb to the top of the Bank of America in downtown Orlando to raise money for research on lung diseases. If anyone is interested in donating or forming a team, contact me. If I raise $1,000 I will do the climb wearing 100 pounds of weight plates, or a 100 pound weight vest if I can borrow one or get one from a sponsor.

Drew Baye Miscellaneous

The American Council on Exercise has now also released a statement about the Time magazine article, and are just as mistaken in most of their points as the American College of Sports Medicine in their response. The following is their editorial (inset) along with my comments:

Editorial: Why Time Magazine’s Article on Exercise and Weight Loss Could Be Harmful to Your Health

By Cedric X. Bryant, Ph.D., F.A.C.S.M., Chief Science Officer, American Council on Exercise

The cover story of the August 9, 2009, issue of Time magazine featured an article entitled, “Why Exercise Won’t Make You Thin.” In this piece, author John Cloud made several inaccurate and unsubstantiated claims regarding the value of exercise, particularly as it relates to weight loss. What follows is a summary of some of the most misleading assertions made in this highly publicized article, as well as the American Council on Exercise’s response to these assertions:

• First and foremost, the article categorically implies that exercise has no meaningful role in weight loss. Such a conclusion is as false as it is reckless. The author’s “evidence” is the fact that he has “gut fat that hangs over his belt when he sits,” despite maintaining a regular exercise habit. In all likelihood, his unwanted abdominal girth is probably a by-product of genetics and/or consuming more calories than he expends.

First off, I should clarify most people’s goal is not indiscriminate weight loss, but improved body composition. This means improving the ratio of muscle to fat, and in most people’s case requiring a significant reduction in fat while minimally maintaining muscle mass. If a person lost 10 pounds of muscle they’d have lost weight, but would look worse and be weaker and less fit. So while ACE use the term weight loss, I’m going to write fat loss, because that’s what people really want.

Second, while genetics plays a role, with a few very rare exceptions it is not an excuse for being fat. Being fat is almost entirely a matter of overeating, and not, as Bryan partly implies in the phrase “…consuming more calories than he expends” that low expenditure is the problem.

I got ripped for a bodybuilding competition doing one high intensity strength training workout per week consisting of only one set each of a few exercises, and lasting around 15 to 20 minutes. Other than that, I was training clients, attending classes or labs, or studying, and actually went out of my way to be less active, as part of the point of entering the contest was to demonstrate it could be done without “cardio”. Clients who follow my nutritional advice consistently lose bodyfat without doing any exercise or increasing their activity levels beyond the one or two weekly workouts they do with me. Read more…

Drew Baye Fat Loss

Fitness and weight loss “experts” like to recommend finding ways to incorporate more physical activity into daily life, usually exchanging efficiency or convenience for increased physical exertion, based on the mistaken belief that doing so makes a meaningful contribution to health, fitness, or fat loss. They claim these little changes add up to a lot of calories burned over the course of a week, however this is not the case. If hour-long “cardio” sessions barely burn enough calories to be worth doing for that purpose, a few minutes walking up the stairs or across a parking lot are hardly going to amount to any calories burned, while reducing your time and productivity.

Unless you enjoy these activities for their own sake, doing them to burn calories is not worth your time. You could accomplish as much of negative calorie balance in a single day with a few dietary changes as the typical recommendations for increases in activity would amount to over several weeks, without it costing a minute of your time.

In a recent post I mentioned a study from the 2009 European Congress on Obesity (Swinburn BA, et al “Increased energy intake alone virtually explains all the increase in body weight in the United States from 1970s to the 2000s” ECO 2009.) which showed a lack of activity is not the problem. Overeating is. If you want to lose fat, forget about spending a few extra minutes walking an extra block to work; you’ll barely burn the amount of calories contained in a few french fries. Instead, save yourself a few minutes and skip the french fries to begin with.

The following are just a few suggestions for dietary improvements that will make a much bigger difference in fat loss than adding a few minutes of extra activity throughout your day:

• Eliminate or minimize intake of grains and other refined carbohydrates.
• Replace them with a variety of fresh vegetables and fruits, especially leafy vegetables and berries.
• Choose leaner sources of protein – some fats are healthy in moderate amounts but fat is very calorie dense.
• Substitute water or other non-caloric beverages like tea for sodas and fruit juices.

This is not to say I believe people should be inactive. There are other benefits to getting up and moving around. However, doing so makes little or no positive difference in body composition.

The only worthwhile exercise for improving body composition is strength training. High intensity strength training in particular provides the greatest physical benefits relative to the time invested, including all of the cardiovascular and metabolic benefits of aerobics or “cardio”. Strength training directly improves body composition by increasing muscle mass and by preventing loss of muscle mass while fat is lost in people restricting calorie intake, and indirectly because more muscle mass equals a higher basal metabolic rate and more storage space for glucose (as glycogen). High intensity strength training also depletes muscle glycogen levels, so more of the carbohydrate consumed is stored as glycogen in the muscles than as triglycerides in the fat cells.

So, if you’re in a hurry to get to work or have better things to do with your time, go ahead and take the elevator or park in the closest spot – you’re not missing out on any kind of major calorie-burning or conditioning benefits. If you need to lose fat, focus on improving your diet instead.

Drew Baye Fat Loss

The upcoming high intensity bodybuilding book will be released as both a paperback and an e-book. The finish line is in sight, and I’m finally happy with the way it’s reading. A big part of the process has been trimming the fat to keep things focused and concise and structuring the book so people can find the information they want quickly and easily.

Anyone who purchases a phone consultation or distance training package between now and the book release (estimated release date 9/14/09) will receive both the paperback and e-book versions free. For the first 30 days after the book is released, anyone who purchases either the paperback or e-book will receive a discount equal to the purchase cost on a phone consultation or distance training package.

In a few weeks I will also be offering an intensive 12-week fat loss program locally which will be available to a limited number of participants and include workout program and diet design. More information will be posted before the end of this month.

Drew Baye Miscellaneous

My friend Anthony Semone informed me the ACSM have posted a press release titled “Experts Debunk Myth About Exercise, Weight Loss” in response to the Time Magazine article covered in my previous post. The following is the full text of their press release (inset) along with my comments:

EXPERTS DEBUNK MYTH ABOUT EXERCISE, WEIGHT LOSS
Research proves value of exercise, nutrition

According to John Jakicic, Ph.D., FACSM, “There is strong evidence from the majority of the scientific literature that physical activity is an important component for initial weight loss.”

INDIANAPOLIS – Leading experts in exercise and weight management have taken strong exception to assertions that exercise can inhibit weight loss by over-stimulating the appetite.

The “experts” can take exception all they like, but it does not change the fact increased activity stimulates appetite and if a person is not measuring and restricting calorie intake they are more likely to end up with a positive energy balance, resulting in an increase in body fat. While exercise burns very few calories, hardly enough to be worth doing for that purpose, a large amount of calories is very easy to consume.

General physical activity and the types of exercise commonly recommended for fat loss contribute relatively little to a fat loss program, and will make either no difference at all or even make things worse if diet is not being controlled. Read more…

Drew Baye Fat Loss

The August 17, 2009 issue of Time Magazine contains an article that is going to piss off a lot of people in the fitness industry, because it challenges one of the biggest myths that have been lining the pockets of gyms, trainers, and equipment companies for years: that exercise will make you lose weight.

The article by John Cloud, Why Exercise Won’t Make You Thin, explains how exercise, which does not burn a significant amount of calories to begin with, stimulates an increase in appetite and compensatory eating. According to one study, this compensatory eating may exceed the calories burned during the activity by as much as 100 – enough to cause a fat gain of over 10 pounds per year. One study mentioned showed no difference in fat loss between three exercising groups and a non-exercising control. This is bad news for aerobics instructors and trainers selling various types of “cardio” classes as an effective method of fat loss.

Actually, this is not news at all. I’ve been telling people this for years, and the people at Nautilus were saying the same thing way back in the ’70s. No activity burns enough calories to be worth doing solely for that purpose. The biggest contribution exercise makes to a fat loss program is the preservation of lean body mass while fat is lost. Any contribution to increased calorie expenditure, either as a direct result of the workout or indirectly as a result of increased muscle mass, is minor compared to the role of diet. Read more…

Drew Baye Fat Loss

New York-based HIT personal trainer Eugene Thong informed me of a recent article in Science Daily about a study from Tel Aviv University showing high carb foods can cause heart attacks.  One more reason to pass on the bread, rice or pasta and opt for better carbohydrate sources like leafy vegetables and fruits.

http://www.sciencedaily.com/releases/2009/06/090625133215.htm

According to the article, study participants had reduced arterial functioning after consuming high glycemic index foods. More specifically, arterial distention, which the authors claim may lead to cardiovascular disease or heart attacks.

The abstract reads:

The Acute Effect of Various Glycemic Index Dietary Carbohydrates on Endothelial Function in Nondiabetic Overweight and Obese Subjects

Talya Lavi, RD*, Avraham Karasik, MD*,, Nira Koren-Morag, PhD, Hannah Kanety, PhD*,, Micha S. Feinberg, MD, and Michael Shechter, MD, MA,,*

* Institute of Endocrinology, Chaim Sheba Medical Center, Tel Hashomer, Israel
Leviev Heart Center, Chaim Sheba Medical Center, Tel Hashomer, Israel
Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel

Manuscript received October 26, 2008; revised manuscript received February 18, 2009, accepted March 3, 2009.

* Reprint requests and correspondence: Dr. Michael Shechter, Leviev Heart Center, Chaim Sheba Medical Center, 52621 Tel Hashomer, Israel (Email: shechtes@netvision.net.il).

Part of this study was presented as an abstract at the XXVI Congress of the European Society of Cardiology, Stockholm, Sweden, August 30, 2005.

Objectives: This study sought to explore the effect of glycemic-index dietary carbohydrates on endothelium-dependent flow-mediated dilation (FMD) in overweight and obese nondiabetic volunteers.

Background: Post-prandial hyperglycemia has been recognized as a cardiovascular risk factor in both the diabetic and the general population. Endothelial dysfunction has been shown to occur in diabetic and hyperglycemic patients.

Methods: We prospectively assessed brachial artery FMD in 56 healthy overweight and obese nondiabetic volunteers (38 [67.9%] men, mean age 48 ± 6 years) on 4 separate mornings, 1 to 2 weeks apart. After overnight fasting, the percent FMD (%FMD) improvement and endothelium-independent nitroglycerin-mediated dilation (%NTG) were assessed, after which subjects received 1 of 4 group meals at each visit (placebo [water] or a carbohydrate meal of glucose, cornflakes, or high-fiber cereal). Meals were distributed in a rotating randomized fashion, such that eachsubject received all 4 meals once throughout the study period.

Results: Fasting and 2-h post-prandial serum glucose levels were similar in all 3 meals, whereas at 30 to 90 min, serum glucose levels were significantly higher after glucose and cornflakes (high glycemic) compared with fiber (low glycemic). Baseline %FMD, not significantly different in the 3 carbohydrate-based meals, was reduced 2 h post-prandially in all groups, showing statistical significance in only high-glycemic index meals: glucose (15 ± 9% vs. 10 ± 8%, p < 0.01), cornflakes (13 ± 7% vs. 9 ± 7%, p < 0.01). No correlation was observed between the %FMD reduction rate and glucose levels throughout the study period.

Conclusions: High- compared with low-glycemic carbohydrate consumption significantly suppresses FMD in nondiabetic overweight and obese volunteers, suggesting a mechanism whereby high-glycemic meals may enhance cardiovascular risk.

Drew Baye Nutrition