Category Archives: Hot Topics
On Blast: CHO or Protein for post-workout recovery?
A metabolic window refers to a time period of approximately 30-60 minutes post-exercise, then again 2 hours later. During this time, a balance between the right proportion of CHO and protein can help the body in recovery following a strenuous workout. Consuming the balanced snack/meal after the window has closed can result in as much as 85% less protein synthesis necessary for muscle recovery. High glycemic index CHO results in higher muscle glycogen 24 hours after vigorous exercise (think PBJ sandwich, greek yogurt & granola, or fruit & cheese).
Recovery nutrition can:
- Reduce an athlete’s susceptibility of becoming sick
- Avoid a negative protein balance
- Avoid muscle hypertrophy
- Improve body responsiveness to recover after a strenuous workout
- Minimize muscle catabolism
- CHO intake post-exercise increases insulin levels = promotes uptake of glucose into the muscles (restores muscle glycogen)
- Combination of CHO and protein intake has proven to be more effective in recovery than focusing solely on either alone.
- 2:1 CHO to protein intake for resistance exercise
- 4:1 CHO to protein intake for glycogen-depleting exercises (distance running)
Verdict: A combination is best! Don’t miss your “window” of opportunity for recovery…har har har
On Blast: Weight gain during training
A strength-to-weight ratio is the measurement comparison of fat free mass to fat mass (equation = fat free mass/fat mass) in the body. A higher strength-to-weight ratio is preferred because it reflects higher free fat mass and less fat mass. I often get asked why weight can change so much during the beginning of new exercise regimens or as the intensity increases during existing training routines. There are 3 scenarios substantiating how strength-to-weight ratio effect total body weight.
- Maintaining fat free mass as fat mass is decreased results in a lower total body weight, which effectively increases the strength-to-weight ratio.
- Increasing free fat mass while maintaining fat mass, increases total body weight, as well as a strength-to-weight ratio.
- Increasing free fat mass while lowering fat mass, lower total body weight and increases strength-to-weight ratio
It’s really not enough to look at weight alone when you are assessing strength-to-weight ratio. You need to look at your body’s composition. Are you increasing or decreasing free fat mass or fat mass? Tracking weight change does track calorie needs, but it doesn’t measure how the energy is being balanced. Keeping track of body composition and strength-to-weight ratio can better assess your progress.
Verdict: Track that body composition!
On Blast: CHO Intake for Athletic Training
It’s spring and I feel like everyone I know is either training for a muddy buddy, a race of some sort, or a triathlon. The more I visit with these individuals, the more I am surprised by their dietary intake and disdain for our friend, The Carbohydrate (CHO). Let’s focus on aerobic training (biking, swimming, running, etc.). As you increase your ability to efficiently intake and utilize oxygen, your body does the same with burning fat. FACT: you cannot burn fat without fueling the process with a CHO. For chem nerds, think of CHOs as that process’ limiting reagent/factor.
CHO Dietary Intake Endurance Results:
- High-fat diet- maximal endurance time of 57 minutes
- Normal mixed diet- endurance rises to 114 minutes
- High CHO diet– maximal endurance rises to 167 minutes
Verdict: Athletics should consume between 7 – 10g CHO /kg of body weight per day.
1 kg = 2.2 lbs. An athlete weighing 150lbs should consume 477-681 g CHO daily (68.18kg x 7-10g).
On Blast: Exercising Your DNA
I have to share this article that I read in TIME Heartland. It’s about a study in which they showed a change in DNA through exercising…seriously. Exercise keeps us lean, lowers heart disease/stroke/diabetes risk, and (as if you need more convincing to work out), now it’s great for our DNA.
In this study, researchers were measuring the activity of a compound called a methyl group. Methyl groups are sticky and love to attach themselves to other compounds. The problem in our bodies is that if you change the structure of something, you change the function. Sometimes this is good, sometimes not so much. Here is one example of why they are important in exercise: these groups prime your muscle cells to ready themselves with energy and nutrients for the impending work they are about to do. One downside to methylation? When a methyl group fixatates itself to a DNA molecule, the alteration to the structure limits gene activity in the molecule. The study describes one example of a cell’s ability to specialize into an eye cell or a liver cell, depending on the amount of methylation to that cell at a given time. Scary.
Researchers here found that the more intense the exercise, the more methyl groups were out and about, rather than settling and fixating immediately. So what else happens with intense exercise? With intense exercise, the more intensity, the more oxygen is consumed to keep up the aerobic work. Oxygen consumption is increased until your body hits its max threshold. This is called the VO2max. Generally, the higher your VO2max is, the more you can sustain high-intensity aerobic work.
Verdict: Project Gym Rat shall commence!
On Blast: The Skinny on Blood Glucose
Did you know that stabilizing blood sugar is the key to maintaining muscle mass, weight loss, and reducing fatigue?
On maintaining muscle mass: Glucose (often referred to as your blood sugar) is the main fuel source for your body during physical performance. As your body requires more fuel, its sources in your body begin to deplete. As you continue your performance, your body eventually can have blood sugar low enough to trigger a “starvation” phase. During this phase, an amino acid named alanine is sent from your muscle tissue to the liver in order to be converted into more glucose. Therefore, in an effort to preserve muscle tissue, it’s a beneficial to maintain your blood glucose (see previous entries on sports beverages and whole grain food choices).
How often we eat can also be important, as shown in previous research. Numerous studies have shown a benefit of consuming smaller meals throughout the day with a set number of calories. Through this practice, insulin response levels were reduced, and blood glucose levels were maintained (when glucose goes up, insulin goes up…so if blood glucose is kept at a healthy level, you see few insulin spikes). Blood sugar tends to rise and fall every 3 hours. By maintaining a 3 meal/day pattern with small snacks in between, a better blood glucose is maintained, and improvement is seen in mental acuity and enhanced athletic performance.
Verdict: Stay sweet! Remind yourself to sip on a glucose source (Gatorade?) every 20 minutes…even if you are not thirsty.
On Blast: Vita Coco vs. Gatorade Smackdown
One coconut water product, Vita Coco, received some bad press last week. Evidently, the company has been marketing its product as a superior sports drink for its “super hydrating” and electrolyte-dense properties claim. A class action has been filed against them for “misrepresentation and omissions.” Yikes!!
So let’s gather the facts and analyze the evidence. We know (from a previous post under “Hot Topics”) that our ideal carbohydrate concentration for an athlete’s sports drink is 7%.
- 46 calories
- K+, Mg+, Vit C
- Na+ 30mg
- CHO 9g
- 50 calories
- K+, Mg+, Vit C
- CHO 14g
If we do the math, Vita Coco provides only 3.75% CHO per 8 fl oz cup, compared to Gatorade’s 5.8%. That is also an incredibly low amount of sodium to consume while exercising. Under the worst circumstances (think hot Houston, Texas sun in late July or August), an athlete loses 15g/2hrs. To do the math, that is 6000mg in 4 hours. You would have to drink 200 cups of Vita Coco to replace that, which is just unsafe and unrealistic. Especially for an athlete, 30mg of Sodium per cup (about the size of a female’s fist) is not going to help you replenish what you’ve lost.
Verdict: Stick with the Gatorade.
On Blast: CHO…love ’em or leave ’em?
Did you know that…
- Your brain runs on carbohydrate. For healthy individuals, it is not recommended to consume less than 180g per day! More for endurance athletes.
- CHOs are the primary fuel for many types of physical activity.
- Consuming CHO before, during, and arter exercise can be imperative for optimal performance.
- Inadequate intake can result in difficulty maintaining activity.
- CHO are the preferred fuel for high-intensity work.
- The only source of high-intensity/short duration fuel can be glucose (a CHO).
- Carbon for Carbon, fat ( 4.62 kcal/L O2) delivers more ATP (energy) than CHO (5.10 kcal/L O2), but requires more oxygen to do so…so the end equation shows CHO to be the best fuel source.
- A low CHO diet (5% of diet) will provide only 1/5 the muscle storage glycogen than a high CHO diet (82%) in athletes. Think about that. You will only be able to do 1/5 the workload on a low CHO diet.
- In another study, runners on a high CHO diet covered a 30k distance faster than those who consume a diet with a normal level of CHO. They had greater muscle glycogen stores = more work accomplished. They did not run faster in the beginning, but the stores prevented them from slowing in the end.
- CHO loading was more effective in men than women. Women tend to have higher fat oxidation (burning) and lower protein/CHO oxidation. Men tend to burn more protein and CHO during intensity. Therefore, it tends to benefit women less and men more to load up on CHOs before an endurance event.
- Research shows that consuming ~4.5g CHO*/kg of your body weight (2.2 lbs = 1 kg) 2-4 hrs before exercise will help restore CHO reserves in muscle, maintain blood sugar levels, and improve endurance performance. (*The closer to the event, the less CHO you should eat and the more time before the event, the more CHO you should eat. Just prior to event, just eat what you need to stay hydrated.)