popular nutrition myths and diets Flashcards
grapefruit burns fat
no foods can burn fat
grapefruits or an citric fruits being able to burn fat has no scientific proof
based on small number of animal studies which suggest that citric acid inhibits fat synthesis and may suppress appetite. these claims have no validity and are inconclusive in animals let alone humans
low fat means low calories
a low-fat or non-fat food is usually lower in calories than the same size portion of the full-fat product because fat contains more calories p/gram than any other macro.
food manufacturers often add sugar, flour and starch thickeners to improve the flavour and texture of the food once the fat has been removed all these ingredients seek to increase calorific value.
eating in the evening causes weight gain
the time of day that foods are eaten does not affect how that food, or the energy within it, is used.
if the body’s glycogen stores are low and carbs are consumed, the glucose digested and absorbed from those foods will be transferred to muscles and liver for storage as glycogen regardless of time of day.
only when the daily energy exceeds the body’s requirements will foods be converted to fat.
skipping meals is good for weightloss
research has consistently shown that people who skip meals tend to be heavier than people who eat a healthy breakfast and eat 4-5 meals a day.
skipping meals triggers the hunger mechanism and is likely to result in poor food choices and binges later on.
food consumption increases body temperature and metabolism.
weight training is no good for weight loss
this is technically true as combined with a diet rich in protein will lead to increased lean mass.
increased levels of lean muscle tissue have the greatest impact on metabolic rate
while weight training exercises don’t burn fat, they do accelerate metabolism and increase daily energy expenditure
lose 20 pounds in 20 days
a weight loss of 1-2 pounds a week is most effective way to ensure sustainable weight loss and that it is primarily being fat lost.
losing weight so fast will be from water, glycogen and lean body mass.
because these diets are always based on calorie restriction, they reduce metabolism rather than promoting it
fat people have slower metabolism
heavier people always expand considerably more energy than lighter individuals at rest and during comparable physical activities
eating fat makes you fat
the consumption of fat doesnt make an individual gain weight, rather it is the overconsumption of energy that is responsible for this.
because each gram of fat contains 2.25 times the number of energy that carbs and protein contain, it is much easier to exceed the daily energy needs with foods containing fat.
the weekend off approach
letting yourself off for the weekend is flawed because considerably more calories than the body actually needs are likely to be consumed. if the deficit created during the week is equal to the excess achieved over the weekend, bodyweight will remain stable.
if even weight loss does occur it is still not healthy one because it is not balanced and weight loss is likely to be lean tissue and water.
set point theory
explained why repeated bouts of dieting were unsuccessful in creating a permanent change in bodyweight.
the set point theory claims that there is an internal control system that is built into each person and that this system dictates how much fat they should carry and store.
if this were true then people with chronic illness and disease who are physically incapable of exercising would not be able to improve their condition by improving their nutritional habits/ also, those who have struggled to manage their bodyweight have the perfect excuse as to why there is little point in improving their eating habits.
atkins diet
4-phase weight loss programme that permits an unlimited amount of high fat and protein foods, but restricts the amount of carbs that can be eaten.
foods allowed on atkins diet
meat eggs cream cheese shellfish butter some vegetables
foods not allowed on atkins diet
processed meats breads grains pasta and rice potatoes margarine most vegetables
Dr Atkins’ primary justifications for his diet
- when carbs are frequently ingested, an over production and release of insulin occurs which results in greater levels of hunger, over-eating and weight gain.
- when foods high in fat and protein are consumed, insulin levels remain low and appetite is supressed because they foods create satiety. usually results in less kcal being consumed overall and weight loss is evitable.
- insulin increases the activity of the enzyme lipoprotein lipase, which is responsible for the storage of fat in muscles and adipose tissue. if insulin levels are kept low, the activity of this enzyme and any subsequent fat storage will also be reduced.
- ketosis increases fatty acid mobilisation; not only is less fat stored, but higher levels of fats are burned because carbs are not available.
- the greater thermic effect of protein and fat reduces the net energy available from the digested foods, compared with the same energy intake from carbs sources. thus the body has to do considerably more work to free the energy contained within the food, reducing the energy that is available for storage following digestion and absorption.
key health risks from atkins
high fat and protein diets often contain large quantities of saturated fats, which increase the risk of heart disease and type 2 diabetes
- diets high in animal fat increase the excretion of a compound called oxalate in the urine. oxalate combines with calcium in the kidneys to form kidney stones.
- ketosis is a form of acidosis and can, if sustained over a long period of time, reduce the body’s ability to manage the acidity of the blood; in extreme cases can lead to blood poisoning.
- the diet is deficient in fibre and promotes dehydration which can increase the potential for constipation and other digestion tract disorders
- not suitable for vegetarians
- diet is deficient in many key vitamins, esp antioxidants and phytochemicals.
- cost of the diet is expensive and would not be practical for the masses. if it were to be adopted universally there would be insufficient food available for the world.
- boredom is common because food choice is restricted
- not suitable for athletes or regular exercises because carbs needed.
the zone diet
- low carb high protein diet.
- claims to change the body’s insulin to glucagon ratio and so promotes fat metabolism rather than storage.
should be 40% from carbs, 30% for protein, 30% from fats
apart from the fact that the diet is incredibly complicated and weight loss that does occur will be from low calorie intake rather than ratio of macros consumed
blood type diet
claims that if you follow a diet specifically designed for your blood type you will lose weight, feel healthier and lower your risk of many diseases.
- suggests that each blood group has its own antigen marker which reacts badly with certain foods.
food combining diet
suggests that combining specific foods inhibits the absorption of nutrients in the digestive tract and this impedes optimal digestive chemistry.
suggests carbs should not be consumed with proteins
there is actually evidence to support eating these foods together - slows down absorption rate which helps curb the rise in blood sugar and control appetite, for longer.
yo yo dieting
describes the cyclical process of food deprivation that many individuals subject themselves to.
each time the diet is repeated the metabolic rate is further reduced by the body’s attempt to create an energy balance.
the long term effects of repeated calorie deprivation reduce the energy expenditure by destroying its reserves of lean tissue; this increases likelihood to gain weight.
you can recover your metabolism.
factors influencing dietary intake
- social
- media
- availability
- family/working practices
- religion
- resources
- education
strengths and weaknesses of high protein low carb diets
strengths = decreased insulin in the blood, decreased fat storage, increased fat usage weaknesses = low energy levels, low fibre, low vitamins and minerals, restricted foods, high in saturated fats, risk of ketosis in highly active individuals
food combining diets strengths and weaknesses
strengths = weight loss from low cals, weight loss occurs rapidly as food type is limited weaknesses = diet is deficient in many nutrients, difficult to eat out, reduces other group food groups
meal replacements strengths and weaknesses
strengths = contains necessary vitamins in shakes or nutrition bars, low in cals and fat, aid weight loss, convenient for dieter weaknesses = products can be expensive, tolerate same taste on a repetitive basis, restricted in cals for people with large build, shakes and nutrition bars are not good long term healthy eating option.
fat burning/ weight loss supplements strengths and weaknesses
strengths = reduce bodyweight, easy to maintain rather than restricting foods, buy over the counter weaknesses = rapid/irregular heartbeats, increased blood pressure, depression, nervousness, insomnia, heart attack/stroke, may contain illegal substances.
elimination/limited food (disordered eating) strengths and weaknesses
strengths = none weaknesses = lack of nutrients, poor health, decreased energy levels, lowers self-esteem, reduces concentration, poor body composition.
Hinduism restrictions and rationale
restrictions = beef, all over meat and fish are restricted or avoided, alcohol avoided, numerous fasting days. rationale = cow is sacred but products of cow are pure and desirable, fasting promotes spiritual growth, generally follow vegan or veggie diet
Sikhism restrictions and rationale
restrictions = beef prohibited and pork not normal, any meat that has ritually slaughtered (kosher, halal etc), alcohol tobacco and drugs are prohibited rationale = to remove unnecessary ritual from their lives and to support one of the four founding taboos in Sikhism. Sikhs spend their lives looking to become one with God and discovering the holy within themselves.
Islam restrictions and rationale
restrictions = pork and certain birds prohibited, alcohol prohibited, coffee/tea/stimulants avoided, fasting from all foods and drink during specific periods rationale = eating is for good health, failure to eat correctly minimises spiritual awareness, fasting has a cleansing effect of evil elements, consume only halal meat.
Judaism restrictions and rationale
restrictions = pork and shellfish prohibited, meat and dairy at same meal prohibited, leavened food restricted, fasting practiced rationale = land animals that do not have cloven hooves and that do not chew their cud are forbidden as unclean (hare, pig, camel etc), kosher process is based upon the Torah
Mormonism restrictions and rationale
restrictions = alcohol and caffeine prohibited, moderation in all foods, fasting practiced rationale = caffeine is addictive and leads to poor physical and emotional health, fasting is the discipline of self-control and honouring to god
Protestant restrictions and rationale
restrictions = few restrictions of food or fasting observations, moderation in eating, drinking, and exercise is promoted rationale = god made all animal and natural products for human enjoyment, gluttony and drunkenness are sins to be controlled.
Rastafarianism restrictions and rationale
restrictions = meat and fish restricted, vegetarian diets only, with salts, preservatives and condiments prohibited, herbal drinks, alcohol, coffee and soft drinks permitted, marijuana used extensively for religious and medicinal purposes rationale = pigs and shellfish are scavengers and thus unclean, foods grown with chemicals are unnatural and prohibited, biblical texts support use of herbs.
Roman Catholicism restrictions and rationale
restrictions = meat restricted on certain days, fasting practised rationale = restrictions are consistent with specific days of the church year
Seventh-day Adventist restrictions and rationale
restrictions = pork prohibited and meat and fish avoided, veggie diet is encouraged, alcohol, coffee and tea prohibited rationale = diet satisfies practice to 'honour and glorify God'
availability
the availability of food will significantly affect the type and volume of food that people can access and consume. People who live in areas with a high amount of fast food restaurants are more likely to consume these.
family/working practices
there is a strong correlation between the eating habits of children and their parents. This includes, likes and dislikes, how they shop, where they shop, brand preferences.
Families with a stay at home mum are more likely to want home-cooked meals, whereas homes in which both parents work, children will more likely be having ready made and microwaveable meals
religion
many religions have very strong beliefs about certain types of food and drinks such as what you can and can’t eat and how the food is prepared.
some religions may temporarily restrict dietary practices around a particular holy day or event
resources
people living in impoverished areas may not have the financial resources to prepare foods at home and may purchase cheap, convenience and processed products from fast food outlets.
those who live in remote areas are far more likely to eat local and seasonal produce than those who live in urban areas near supermarkets
education
those who are educated to a higher level seem to consistently make better food choices and report they know where to source addition nutritional information than those educated at a lower level.
this is also the same for income - very generally speaking, those who earn more tend to make better food choices repeatedly.
