Ch 21: Navigating Diets Flashcards
Dietary approaches can vary based on several factors, including but not limited to the following:
Energy (calorie) control, e.g., calorie counting, points-based commercial diets, or specific meal plans
Macronutrient composition, e.g., low-carb, low-fat, ketogenic, or protein-sparing modified fast
Food type/group choices and/or restriction, e.g., gluten-free, vegan, vegetarian, paleo, clean eating, or Mediterranean
Time-based restriction, e.g., fasting, time-restricted feeding, or cut-off times for meals/nutrients
Degree of flexibility or rigidity of the dietary restraint
It should be noted that in addition to a suitable diet, successful weight loss will also likely include:
Other behaviors, notably physical activity and behavior training such as self-monitoring
The primary weight loss principle
Overall energy balance
Other core principles of a successful diet include:
Macronutrient intake, micronutrient intake, overall food quality, and adherence to the diet.
To assess the potential usefulness of an individual diet method, one can ask the following questions:
- Does this approach lead to superior fat loss compared to other approaches?
- Does this approach lead to superior muscle mass gain (or retention) compared to other approaches?
- Is this approach likely to lead to any micronutrient deficiencies?
- Is the client likely to be able to adhere to this approach?
Does this approach align with the client’s food preference and tolerances? - Is there potential for this approach to cause negative health outcomes (e.g., worsening of blood lipids, insulin sensitivity, or other health markers)?
- Is this approach an evidence-based dietary approach?
Diet Approaches Based on Macronutrient Composition
Low Energy Diets (Calories)
Low Fat
Diets will be of about 800 to 1,200 kilocalories per day (kcal/d)
Low Energy Diets
Diets less than 800 kcal/d kilocalories per day (kcal/d)
Very Low Energy Diets
Advantage of Low Energy Diets
Such diets may be particularly useful in situations where rapid weight loss can have profound health benefits
Negative Effects of Low-Calorie Dieting and Rapid Weight Loss
Increased risk of lean body mass loss, particularly in those who are already relatively lean
Decreased athletic performance
Lowered ability to recover from exercise
Increased hunger versus more moderate calorie reduction (although not always the case)
Decreased food options
Difficulty in consuming sufficient amount of micronutrients
Very Low Energy Diets
Very-low-energy diets (VLED) should be followed only under the supervision of a medical professional. It is beyond the scope of practice for Nutrition Coaches to recommend or oversee the implementation of VLED for clients. A VLED is a doctor-supervised diet that typically uses commercially prepared formulas, such as liquid shakes or bars, to promote rapid weight loss in patients who are obese. VLED formulas are not the same as the meal replacements sold at grocery stores or pharmacies, which are meant to substitute for one or two meals a day.
Suggested Intake of Protein(g/kg)
01.2 to 1.6 g/kg body weight up to 2.3 to 3.1 g/kg fat-free mass
Suggested Intake of Protein(g/lb)
0.5 to 0.7 g/lb body weight up to 1.0 -to 1.4 g/lb fat-free mass
Low Fat Diet
Typically describes a diet where fat intake is 20 to 35% of total calories
Diets below that lower cut-off of 20% of total calories
Very low-fat diets (VLFD).
Potential Negative Impacts of Extremely Low-Fat Intakes
Can limit inclusion of foods with positive health impacts (e.g., nuts, seeds, olive oil, etc.)
Can make the diet more difficult to adhere to due to food restrictions
May lead to decreases in sex hormones such as testosterone (Hämäläinen et al., 1983)
Can lead to increases in triglyceride levels in the blood in the short-term (Lichtenstein & Van Horn, 1998)
Theoretically, can increase the risk of an essential fatty acid deficiency at consistent extremely low-fat intakes (<10% of total calories)
The following are some of the primary explanations for reduced calorie intake on a low-fat diet:
Reduction in calorie-dense foods
Reduction in hyperpalatable foods
Positive Impacts of Dietary Fat
Humans cannot make essential fatty acids, so they must be obtained via the diet.
Fat allows us to absorb fat-soluble vitamins: A, D, E, and K.
Cell walls contain fat.
Fats are involved in hormone production.
Helps avoid problems with low-fat diets
Advise basing most of dietary fat intake
Plant-based fats, particularly those high in monounsaturated fatty acids, as well omega-3 sources, such as fatty fish. In addition, animal foods such as eggs and dairy produce can confer health benefits and should not be avoided due to their fat content.
A study where participants are kept in a ward where they can be closely monitored at all times – this allows for precise measurements of metrics like energy expenditure or precise recording of food intake. These studies are extremely high-quality, well-controlled studies.
Metabolic Ward Study
Studies typically classify a diet as low-carbohydrate if the carbohydrate content is:
40% or less of total calories.
Truly low-carbohydrate, then the carbohydrate intake should be much lower:
50 to 150 g/d (Westman et al., 2007) or < 20% of total calories (Gulbrand et al., 2014).
low-carbohydrate diets
Overall, low-carbohydrate diets can be safely used as a dietary approach to decrease body fat. However, there is no fat-loss advantage over other dietary approaches of equivalent calorie and protein intake. A low-carbohydrate diet is most likely a suboptimal approach for many competitive athletes, particularly in sports with considerable energy contribution from the anaerobic system (Burke, 2015; Burke et al., 2017). A low-carbohydrate diet can be safely used as part of a healthy lifestyle; however, its health impact is dependent on the foods selected and not merely the macronutrient composition
Ketosis
A metabolic state where the liver is producing ketones (or ketone bodies) from fatty acids – there are three ketones produced in the human body: acetoacetate, beta-hydroxybutyrate, and acetone. These ketones are an alternative fuel (substrate) that the body can use during the time of low glucose availability brought on by starvation, very low-calorie intake, and/or carbohydrate restriction (or in clinical disorders).
It involves consuming a large percentage of calories from fat, moderate percentage of protein, and very little carbohydrate.
Ketogenic Diets
A natural metabolic state that occurs when the body starts producing ketones (ketone bodies) from fat. The body can use these ketones as a fuel (substrate) source to generate energy in place of glucose
Ketosis
A ketogenic diet typically requires carbohydrates to be restricted
Less than 50 grams per day (or 5% of total calories), protein intake to be moderate (20 to 30% of calories), and the remaining calories to be made up from dietary fat (usually 65 to 75% of calories).
