NO ROOM FOR COMPLACENCY
- Main reasons for increased life expectancy are
1) Improved sanitation
2) Improved food safety
- Life expectancy for the average American could decline by as much as five years unless
aggressive efforts are made to slow rising rates of obesity
- Quantity and quality of food are important
NUTRITION- ARE YOU CONFUSED YET?
1) Food is complex.
We don’t know the thousands of compounds that occur in natural foods. Even one type
of food grown in a different area has different chemical properties.
2) The interaction between food and physiology is complex.
The way food and human physiology interact is incredibly complicated, and affects
hormonal balance—how your phenotype is expressed.
3) Exercise affects the food/physiology interaction.
Because exercise affects hormonal balance, how you exercise (or if you do not exercise
at all) is a huge factor in the way your body responds to food intake. Many good
epidemiological studies have been conducted on sedentary populations. However,
because there are complex hormonal responses to exercise and food, the questions are
whether these results apply to active populations and, if so, at what level of activity.
4) The way food is grown or reared is vastly different.
For example, some research suggests that you should limit the amount of red meat you
eat. But is meat from a grass-fed, antibiotic-free, and growth-hormone-free animal the
same as meat from a grain-fed animal that is given antibiotics and growth hormone?
What about fruits and vegetables grown with or without pesticides?
5) Nutritional information is contradictory.
There are numerous contradictory statements from nutritional experts. For example, the
general belief is that reducing red meat intake reduces risk of colorectal cancer. But,
paradoxically, beef together with whole milk and dairy derivatives are almost the only sources for conjugated linoleic acids (CLAs), which are the only natural fatty acids
accepted by the National Academy of Sciences of USA as exhibiting consistent antitumor
6) A lot of advice is contrary to “evolutionary logic.”
By this I mean that we evolved eating many foods that we are now told aren’t good for
us; we did not evolve eating many of the foods that we are now told are okay to eat in
huge quantities, such as grains. Given that evolution is one of the few things in biological
science that all scientists agree with, this seems strange.
7) Some long-held beliefs are wrong.
There were some very bad conclusions made from poor research a few decades ago and
some of it has become mainstream belief. This belief is very hard to shift out of the
8) Some research has been conducted incorrectly.
Further nutritional research set out to prove what we “already knew,” and this is simply
not the way scientific research is supposed to be conducted.
9) There are too many rules for the general public to “digest.”
Nutritionists want to be complete in their analysis, but providing too many rules means
too much confusion for the general population.
10)Nutritional guidelines are not objective.
Food manufacturers were involved in the development of government-sponsored
nutritional guidelines. This is far from objective.
11)Manufacturers make unreliable claims.
Advertisements from food manufacturers often state that their nutritional claims are
based on “scientific studies.” The general population does not have time to investigate
these claims and the regulation of such claims appears quite lax. The population is led to
believe that these claims must be true, which is not always the case. AN EVOLUTIONARY PRESPECTIVE ON NUTRITION
- The problem with the study of human nutrition is that it lacks a universally
acknowledged, unifying paradigm
- Human nutritional requirement were genetically determined
- There is a strong evidence that the obesity problem has been caused by a heavily
reliance on sugar, refined carbohydrate, and other processed foods in our diets , and a
sedentary lifestyles and lack of exercises
- Cow’s milk (but there is chemical evidence for dairying in the form of residues of dairy
fats on pottery around 6100-5500 BC in Britain)
- Cereal grains (agriculture started around 10,000 years ago).
- Table salt (but excavated ancient saltworks are thought to date back to at lest 6000 BC)
- Processed sugar (introduced after 1800).
- Highly processed foods (introduced mostly after 1800).
- Pesticide residues (introduced after 1930).
- Radioactive foods (introduced after 1945).
- Artificial/synthetic additives (introduced mostly after 1950).
- High-fructose corn syrup (HFCS) (mass produced from 1965).
- Genetically modified food (introduced since the 1990s).
Paleolithic food pyramid
- Stone age humans died ( on average) much earlier than we do because of infectious
disease that we have since learned to control PROBLEMS WITH PALEOTHIC NUTRITION
- Eating a strict Paleolithic diet is incredibly difficult in our society
- Food that would be acceptable on a strict Paleo diet is hard to find, spoils very easily,
and is usually expensive
What is “the” Paleolithic diet and could you actually eat such a diet today?
- No one can agree on what Paleolithic diet is
- Most foods that we evolved eating are no longer available to us today, either in type of
Food isn’t poison
- Modern food isn’t strong poison
- Some modern food behave like slow-acting poisons, a heavy reliance on these foods will
wreak havoc with our health
Humans adapted to a wide variety of foods
- Ancestors would also had widely varied diets
- Epigenetic adaptations are changes in phenotype (gene expression) caused by
mechanisms other than changes in the underlying DNA sequence
- Changes may remain through cell divisions for the remainder of the cell’s life, and may
also last for multiple generations
- There is no change in the underlying DNA sequence; in effect, non-genetic factors are
causing the organism’s genes to behave or “express themselves” differently
- Epigenetic marks on DNA change over a person’s lifetime, and the changes are similar in
- Overall genome health is inheritable and that epigenetic changes that occur during a
person’s lifetime may explain why susceptibility to disease increases with age
Did Paleolithic humans eat starchy tubers?
- Tubers are swollen, underground plant parts that store food
- Exp. Potato, turnips, cassava, yams
- Cannot be eaten raw - During human evolution, duplication of certain genes occurred that allowed humans to
more easily subsist on tubers
- Advice to avoid potatoes might not be correct if early humans had developed genes that
specifically allowed for better breakdown of starchy food
- It requires a reliable supply of sugar to fuel brain growth
- Starch may be a natural human food, most hunger-gatherer groups consume
- Starchy tubers may have supplemented this diet, providing extra energy, or glucose,
needed for brain growth
- We couldn’t sustain the current human population if we all eat Paleo diets
- Abundant calories have facilitated human population growth
- Agriculture has allowed us to congregate in large cities, which has helped cultural
- There is problem finding natural foods similar to what our ancestors would have eaten
- There is issue of pesticides used in growing fruit and vegetables
- Organic foods are expensive, but is far more nutritious than ordinary produce, and can
help improve health and longevity
- You should eat food you believe will help you keep you healthy
Support for reducing processed and “new” foods
- Traditional, un-processed diets did not cause the health problems that we afflict our
- Modern processed food, overwhelming amount of sugar, refined carbohydrate,
high-fructose corn syrup, fructose, trans-fats, and chemicals in those processed foods,
are the main reason – along with lack of exercise- behind the current epidemic of
obesity and metabolic derangements
POOR RESEARCH AND ANCEL KEYS
- The close you can move your diet to Paleo nutrition, the healthier you will be
- Nutrition did have a unifying paradigm
- Low-fat diets failed d Influential studies
- Ancels key charted the consumption of fat in seven countries, relative to their rate of
- The science supporting low-fat diet is weak
- When you eat carbohydrates with a high-glycemic index, the body releases excessive
amounts of insulin rapidly
- The insulin spike is designed to remove blood glucose quickly and the body stores it as
fat in the cells
- Insulin levels have spiked to a high level, insulin stays in the blood stream for quite some
- Drives blood glucose levels lower than ideal, which causes hunger because the brain
thinks that there is no more energy left to use
- The result is often that you consume another high-GI meal and repeat this cycle
- If you balance the meals and eat low-GI foods, you will not be hungry as soon after the
- The hormonal response to food means there is more to meal design than counting
- GL = GI xCarbohydrate (grams) / 100
- Glycemic load (GL) takes into account fibre content and portion size
- Soluable fire, fat, acidic foods, and protein lower insulin levels
- Low fat high carbohydrate diets provide no added cardiovascular benefits and may
actually be harmful in terms of increasing incidence of syndrome X
- Hyperinsulinemia: a condition in which excess levels of insulin are circulating in the
- Reducing carbohydrate intake by lowing triglycerides and favorably altering blood
cholesterol profiles can reduce risk of cardiovascular disease
- Regulating blood insulin level by lowering carbohydrate intake may reduce the risk of
developing syndrome x
1) Promote moderate consumptions of all meat
2) Increase consumption of goods rich in complex carbohydrates
3) Encourage use of skim milk and low-fat cheese
- Oscam’s razor: the explanation of any phenomenon should make as few assumptions as
possible, eliminating those that make no difference in the observable predictions of the
explanatory hypothesis or theory
- “ all other things being equal, the simplest solution is the best” - When multiple, competing theories are equal in other respects, select the theory that
introduces the fewest assumptions and postulates the fewest entities
GOVERNMENT AGENCY ADVICE ON NUTRITION
- The government still promotes advice suggesting that grains are good and too much
meat is bad
- Researchers argue that government-ordained food pyramids is inadequate as health