What is the Glycemic Index (GI) and how does it relate to blood sugar levels?
The Glycemic Index (GI) is a ranking of carbohydrates on a scale from 0 to 100 based on how much they raise blood sugar levels after eating. Different carb sources can affect the rate at which glucose appears in the blood.
Does the type of carbohydrate affect fat loss?
No, diets with different sugar levels but the same number of calories result in the same body composition. Simple and complex carbs are equally fattening.
1/49
Glycemic Index and Blood Sugar Regulation

What is the Glycemic Index (GI) and how does it relate to blood sugar levels?

The Glycemic Index (GI) is a ranking of carbohydrates on a scale from 0 to 100 based on how much they raise blood sugar levels after eating. Different carb sources can affect the rate at which glucose appears in the blood.

Carbohydrate Intake and Fat Loss

Does the type of carbohydrate affect fat loss?

No, diets with different sugar levels but the same number of calories result in the same body composition. Simple and complex carbs are equally fattening.

Types of Carbohydrates

What are complex carbohydrates?

Complex carbohydrates have three or more sugars and include oligosaccharides and polysaccharides.

Lactose Intolerance and Its Effects

What is lactose intolerance and who is most affected by it?

Lactose intolerance is the inability to digest lactose due to low lactase activity, leading to discomfort, bloating, and abdominal distension. It is particularly prevalent in African Americans, Jews, Arabs, Greeks, and some Asians.

Glycemic Index and Blood Sugar Regulation

Does the glycemic index of a diet determine its effects on body composition?

No, numerous studies have shown that low-GI diets are no better than high-GI diets for reducing body weight or body fat.

Role of Fiber in Health

How does fiber benefit health?

Fiber improves digestion, glucose control, and immune system function. It also lowers the risk of cardiovascular diseases, aids fat loss, and increases gut microbiota diversity.

Role of Fiber in Health

What are the daily fiber intake recommendations for men and women?

The daily fiber intake recommendations are 38g for men and 25g for women.

Types of Carbohydrates

What are simple carbohydrates?

Simple carbohydrates include monosaccharides and disaccharides such as glucose, fructose, lactose, maltose, and sucrose.

Digestion and Absorption of Carbohydrates

What happens to carbohydrates by the time they are fully digested?

By the time carbohydrates are fully digested, they are broken down into monosaccharides glucose, fructose, and galactose.

Carbohydrate Tolerance and Insulin Sensitivity

What is carbohydrate tolerance and how does it vary among individuals?

Carbohydrate tolerance refers to how well an individual can handle carbohydrate intake without adverse effects. It varies based on factors like insulin sensitivity, body composition, and genetic predisposition.

Types of Carbohydrates

What are polysaccharides and where are they found?

Polysaccharides include starch, glycogen, and cellulose. Starch is found in cereal grains, potatoes, legumes, and other vegetables.

Fructose Metabolism and Toxicity

What are the potential health risks of high fructose consumption?

High fructose consumption can lead to de novo lipogenesis, resulting in triglyceride accumulation in the liver, insulin resistance, chronic inflammation, and increased risk of cardiovascular disease.

Glycemic Index and Blood Sugar Regulation

How does insulin regulate blood glucose levels?

Insulin helps lower blood glucose levels by inhibiting gluconeogenesis in the liver and facilitating glucose uptake by cells.

Practical Applications of Carbohydrate Consumption

What are the practical applications of carbohydrate consumption for strength trainees?

Strength trainees should consume some carbs before and after workouts, but overall carb intake is less critical than protein intake for muscle growth and performance.

Energy Production from Carbohydrates

What is the role of glycogen in energy production during exercise?

Glycogen stored in muscles and the liver is broken down into glucose to provide energy during exercise, especially during high-intensity activities.

Types of Carbohydrates

Where are oligosaccharides found and why do they cause flatulence?

Oligosaccharides are found in beans, peas, bran, and whole grains. They cause flatulence because digestive enzymes cannot hydrolyze all kinds of oligosaccharides, leaving bacteria in the intestines to digest them.

Fructose Metabolism and Toxicity

How is fructose metabolized in the body?

Fructose is primarily metabolized in the liver, where it can be converted to glucose, stored as liver glycogen, or broken down into pyruvate for energy. It can also be converted to fatty acids.

All types of carbohydrates consumed eventually end up as either ______ or ______ as the metabolic byproducts after digestion.

<p>glucose; fructose</p>

Large fructose and sugar alcohol intakes can lead to:

<ol class="tight" data-tight="true"><li><p>Diarrhea</p></li><li><p>Bloating</p></li><li><p>Stomach cramps</p></li></ol><p></p>

Is fructose toxicity a concern for people?

<p>Fructose toxicity is only a concern for people who consume large amounts of processed foods with added fructose.</p>

Why does insulin by itself not make someone gain fat?

<p>Insulin cannot store what isn’t there - energy balance still applies. If insulin made someone fat, anyone on a high-protein diet would become fat as protein is insulinogenic. At the end of the day, when it comes to fat loss, a carb is a carb.</p>

How can eating carbohydrates increase fat gain?

<ol class="tight" data-tight="true"><li><p>First off, you would need to be in an energy surplus. </p></li><li><p>The body preferentially stores fat as fat and burns carbs for energy; however, any carbs you eat and burn as energy frees up more fat that you consumed to be stored as fat.</p></li><li><p>When your body’s fat storage rate exceeds what it can use from your dietary fat intake, it can convert the carbs you intake to fat via de novo lipogenesis.</p></li><li><p>Overfeeding on carbs will cause increased glycogen storage after which extra de novo lipogenesis occurs to store the remaining carbohydrate excess.</p></li></ol><p></p>

The development of type II diabetes can have 2 stages of carb intolerance:

<ol class="tight" data-tight="true"><li><p>There is insulin resistance with high insulin production but not too high blood glucose levels.</p></li><li><p>Later, insulin production becomes exhausted and blood glucose levels rise as a result.</p></li></ol><p></p>

Blood sugar is inherently inflammatory b/c it causes _________.

<p>oxidative stress</p>

Excessively elevated _________ levels may impair _________ by causing _________ and thereby interfering with the inflammatory signal for muscle repair.

<p>blood glucose<br>nutrient partitioning<br>chronic inflammation</p>

Poor insulin sensitivity can reduce ________ which decreases ________.

<p>TEF<br>energy expenditure</p>

Since insulin has an ________ effect, fluctuations in insulin levels can cause similar fluctuations in _________.

<p>appetite suppressing<br>hunger levels</p>

How can carbohydrates cause carb-intolerant individuals to reduce their spontaneous physical activity and the amount of effort they put forward in training?

<p>Carbohydrates stimulate both serotonin and dopamine production. While these neurotransmitters are normally well-regulated by the body, if an individual has abnormal levels of either, carbohydrates can significantly impact their physical and mental performance and their motivation.</p>

If you do not have access to someone's bloodwork, how else may you be able to determine if someone is carb intolerant?

<ol class="tight" data-tight="true"><li><p>High BF%</p></li><li><p>Genetic ancestry is close to Africa or India</p></li><li><p>Men and women with PCOS (normally women are unlikely to become carb intolerant due to superior insulin and glucose metabolism)</p></li><li><p>Older individuals</p></li><li><p>Sedentary individuals</p></li></ol><p></p>

What is the best way to test if someone is carb intolerant and what should the test consist of?

<p>Bloodwork. Do a panel for type-II diabetes and the test should consist of:<br>1. An oral glucose tolerance test that measures fasting blood glucose and postprandial glucose after a high-carb meal;<br>2. Fasting insulin concentration; and <br>3. A glycated hemoglobin (A1C) test - a measure of average blood glucose levels over the past few months</p>

Nearly all energy formed from the oxidation of carbohydrates to CO2 and H2O is released via the ________.

<p>TCA (Krebs) cycle</p>

What are the energy production pathways?

<ol class="tight" data-tight="true"><li><p>Creatine phosphate system (phosphocreatine system, ATP-CP)</p></li><li><p>Glycolytic system (anaerobic glycolysis, lactate system)</p></li><li><p>Aerobic system (aerobic glycolysis, TCA cycle)</p></li></ol><p></p>

What limits the aerobic system and how much ATP it can produce?

<p>The aerobic system depends on oxygen, therefore it is limited by VO2 max (the point at which further increase in exercise intensity can no longer produce an increase in the volume of oxygen uptake).</p>

Above __% VO2 max, carbohydrates supply the vast majority of energy.

<p>85</p>

Fatty acids are the favored substrates for intensities of up to about __% VO2 max.

<p>50</p>

As exercise intensity increases to __% VO2 max, the relative contribution of _______ oxidation to total metabolism increases sharply.

<p>85; carbohydrate</p>

Most energy (ATP) from the ATP-CP system is exhausted within _______ and is generally fully replenished within _______.

<p>10-25 seconds; 3 minutes</p>

How is ATP produced when the body relies on the glycolytic system for energy production?

<p>ATP is produced by the incomplete, anaerobic breakdown of glucose through phosphorylation into lactate.</p>

How much glycogen is typically stored in skeletal muscle and the liver?

<p>Skeletal muscle: 350-500 g<br>Liver: 80-120 g</p>

What is the key difference between muscle glycogen and liver glycogen?

<p>Muscles can only use their locally stored glycogen as fuel. The liver can breakdown its glycogen into glucose where it re-enters the bloodstream to be absorbed and used by the skeletal muscles that need it. </p>

Why is the liver crucial is maintaining blood glucose homeostasis?

<p>The liver can both produce glucose (via breaking down its glycogen stores) and reduce blood glucose levels when these levels become too high.</p>

Specifically regarding strength training, what are 2 scenarios in which carbohydrate intake becomes more important?

<ol class="tight" data-tight="true"><li><p>Performing over 10 sets per muscle group in a single workout.</p></li><li><p>Training twice on the same day with high volumes.</p></li></ol><p></p>

Why are carbohydrates generally not as important for strength training in contrast to popular belief?

<p>It can be posited that generally you only need ~80 g of carbs to fuel a typical strength training workout. This assumes:<br>- 500 kcal expended<br>- 16% of energy is produced by the ATP-CP system (lower end of range based on research)<br>- 20% of energy is produced by the aerobic system (lower end of range based on research)<br><br>Since your skeletal muscles store between 350-500 g, you would not exhaust your glycogen stores from the workout. You can also expect to achieve full glycogen resynthesis before your next workout (even if it is the following day).</p><p></p><p></p>

List and describe the 3 mechanisms by which the body can produce glucose without using any carbohydrates (gluconeogenesis).

<ol class="tight" data-tight="true"><li><p>Amino acids - all amino acids except lysine and leucine are gluconeogenic and therefore can be converted into glucose.</p></li><li><p>Fats - the glycerol backbone from triglycerides can be converted into glucose by the liver; therefore if someone is on a low-carb, high-fat diet (e.g., keto) then there should be an adequate supply of TAGs to make a major conversion of glycerol to glucose plausible.</p></li><li><p>Lactate - the Cori cycle recycles lactate produced during anaerobic exercise into glucose.</p></li></ol><p></p>

What two things are needed to maximize glycogen resynthesis in the muscles?

<p>insulin and glucose</p>

Do you absolutely need to consume carbohydrates post-workout (strength training workout) if you are already consuming an adequate amount of high quality protein?

<p>No. Carbohydrates do not contribute to or improve MPS but they do suppress MPB due to triggering an insulin release. However, protein is also insulinogenic and it also stimulates MPS. Therefore, it is redundant to consume carbohydrates post-workout if you are already consuming enough high quality protein (at least 0.4 g/kg).</p>

How does soluble dietary fiber make you feel full?

<p>The fiber binds to water and certain nutrients which turns the fiber into a thick, viscous gel which delays gastric emptying and food transit times.</p>

What are the benefits of consuming dietary soluble fiber?

<ol class="tight" data-tight="true"><li><p>Reduced LDL levels</p></li><li><p>Reduced blood pressure</p></li><li><p>Improved blood sugar levels</p></li><li><p>Improved insulin sensitivity</p></li></ol><p></p>

Why can someone start losing weight just by increasing their fiber intake?

<p>Dietary soluble fiber generally contains 2 kcal per gram (and sometimes even less or negative calories) due to their anti-nutritive effects. An increase in dietary fiber intake can decrease energy balance by a few percent due to fecal energy losses (literally “pooping out energy”).</p>

Study Smarter, Not Harder
Study Smarter, Not Harder