Chapter 7

Nutrients

Some nutrients are needed in small amounts and are thus called micronutrients and we will discuss theses shortly. Other nutrients are needed in vastly larger amounts because they contain useable energy (calories) and/or essential amino acids. These are called macronutrients.

 

Macronutrients:

Macronutrients are nutrients that provide our bodies with energy. This energy is contained in the chemical bonds

There are three basic macronutrients: fat, carbohydrate and protein. They each have substantially different chemical and physical properties, but they all contain useable calories. Two macronutrients are essential, we cannot live long without them: fat and especially protein. Carbohydrate is not absolutely needed for life though it clearly IS needed for optimal health.

Some of the properties of each macronutrient are listed below. We will explore these properties in great detail later.

 

FAT

Carbohydrate

Protein

Alcohol

Cal Per Gram

9

4

4

7

TEF

2%

~10%

30%

30%

Essential?

Yes

No

Yes

No

Sources

Oils

Starch/Sugar

Egg, Dairy Meat

Fermented sugar

Min RDA

Complicated

None

~50 grams

None

Weight Loss

50 grams per day

Unlimited for low-glycemic index Carbs

100-130 grams per day

Not applicable

 

 

 

 

 

 

Macronutrients & Weight

Macronutrients are the fuels of the body. These are the nutrients in food that actually contain calories. Other nutrients, like vitamins and minerals are essential to health and life, but they generally lack calories.

The "Big Three" Macronutrients: Fat, Carbohydrate and Protein

Calorie-containing nutrients can be divided into three basic types that differ dramatically in their  chemical properties. These three types are fats, carbohydrates and proteins.

Macronutrients are More Than Just Calories

Macronutrients provide the body with essential fats and amino acids without which we will die--even if we get enough calories.

Macronutrients are Drugs & Hormones  that Affect Body Weight

Fats, carbohydrates and proteins all affect body weight not just because of calories but because they alter appetite and metabolism in complex ways. In other words, food choices affect weight not just because of calories, not just because of non-caloric chemicals found in some foods, but because the very components of food that contain calories also affect weight because they act as drugs and hormones.

My goal in writing this chapter is to help you understand the true complexity of diet and why choices that have nothing to do with calories matter so much.

1.     Fats

a.     Basic Properties

                                          i.    Approximately 9 calories per gram

                                         ii.    Generally fats do not mix with water

                                        iii.    Lowest thermic effect of the three macronutrients (~2%)

                                        iv.    Most (but not all) dietary fats are triglycerides composed of one glycerol molecule and three fatty acid molecules.

b.    There are Many Types of Fats with Many Different Effects Upon Weight and Health

                                          i.    Unsaturated Fats: Unsaturated fats tend to be liquid at room temperature and include most vegetable oils. "Unsaturated is an organic chemistry term that means these fats have "double bonds" in them. The location of these double bonds and the size of the fat determine it's effect on health. Some unsaturated fats are very bad for health and some are extremely good for health.

1.     Trans-fats: There are bad transfats (manmade) and good transfats (natural)

a.     Man-made trans-fats are universally bad.

                                                                                          i.   Manmade trans-fats cause weight gain and metabolic problems

                                                                                         ii.    There is NO healthy level of manmade trans-fat.

                                                                                        iii.   Manmade trans-fats are an inevitable consequence of the PARTIAL hydrogenation of vegetable oil (the "oleo" process traditionally used to make shortening (Crisco) and margarine. Any and all food containing "partially hydrogenated vegetable oil" contains trans-fat and should be avoided.

                                                                                        iv.    The label "no trans-fat" or "trans-fat-free" means that the product contains LESS THAN ONE-HALF GRAM per serving. This means that the food MAY be truly free of trans-fat or it may not be. The only way to know for sure is to read the ingredients and make sure that there is no "partially hydrogenated vegetable oil".

                                                                                         v.    "Fully hydrogenated vegetable oil" does NOT contain transfat.

b.    Natural trans-fats MAY improve health and weight loss

                                                                                          i.   "Conjugated Linoleic Acid" (CLA) is the most important and beneficial natural trans-fat. CLA has appears to improve weight loss in humans and laboratory animals

                                                                                         ii.    CLAis found in lamb, red meats and dairy. The amount ofCLA found in these meats depends, to a large extent, upon the diet of the animal.

2.     N-6 unsaturated fats (Essential in low-doses, bad in high doses)

a.     N-6 refers to the location of an unsaturated fat's double bond.

b.    N-6 fats are pro-inflammatory (they promote inflammation which makes obesity and obesity-related conditions worse)

c.     N-6 fats are found in vegetable oil like soybean oil (generic 'salad oil' or 'cooking oil'), cottonseed oil, peanut oil, corn oil and peanut oil.

d.    Small amounts of n-6 fats are essential but are best obtained from high n-3 oils.

3.     N-3 fats (VERY Good):

a.     N-3 fats are also called 'omega-3' fats or 'omega-3 fatty acids'. They all mean the same thing.

b.    N-3 fats are anti-inflammatory (they reduce inflammation which is generally beneficial to health and weight.

c.     N−3 fatty acids that are important in human physiology areα-linolenic acid ,eicosapentaenoic acid anddocosahexaenoic acid.

                                                                                          i.    Alpha Linoleic Acid (ALA)

1.     Found in flaxseed oil and to a lesser extent, in tree nuts, especially pecans

2.     Also found in eggs from soy and corn-fed chickens and from grass-fed beef

3.     ALA is beneficial, but EPA and DHA are better.

                                                                                         ii.   Eicosopentaenoic Acid (EPA) and Docosahexaenoic acid (DHA): (Fish Oils)

1.     EPA and DHA both play important roles in human health both by reducing inflammation, reducing risk for heart disease and promoting weight loss.

4.     Monounsaturated Fatty Acids (MUFAs)

a.     MUFA's are extremely heart-healthy but they probably do NOT promote weight loss.

5.     Polyunsaturated Fatty Acids (PUFAs)

a.     PUFA's are generally heart-healthy but probably do NOT promote weight loss

6.     Diacylglycerols (DAGs) also called "Diglycerides"

a.     Glycerol can "bind" as many as three fatty acids but can also bind only one or two.

b.    DAGs may increase fat-burning.

c.     A Japanese company marketed a DAG oil called ENOVAfor several years in several countries during the mid-2000s

d.    ENOVA contained about 80% DAGs and was manufactured chemically

e.     ENOVA was voluntarily withdrawn from the market by its manufacturer because of concerns that a by-product from manufacture may be dangerous.

f.     Once again, synthetic foods seem to carry more risks than many natural foods.

7.     Medium Chain Triglycerides (MCTs) & Medium Chain Fatty Acids (MCFAs):

a.     MCTs are dietary triglycerides containing three MCFAmolecules. MCTs and MCFA's therefore have similar properties.

b.    MCT's are found abundantly in coconut oil but coconut oil also contains saturated fats.

c.     Purified MCT's appear to promote weight loss in animals and people, but with some important caveats:

                                                                                          i.    MCTsimprove weight loss when the REPLACE other fats in the diet. Adding MCTs on top of a diet already high in fat won't help.

                                                                                         ii.   Significant weight loss is only seen with MCTs when large amounts of them are consumed.

                                                                                        iii.    MCTspromote weight loss in two ways:

1.     They have a higher thermic effect than other fats. In other words, they increase calorie burning after a meal containing them.

2.     They are metabolized into compounds that suppress hunger.

                                                                                        iv.    Pure "MCT Oil" is expensive

 

                                         ii.    Saturated Fats: Saturated fats are fats that tend to be solid at room temperature. The term "saturated" comes from organic chemistry and refers to the fact that these fats are saturated with hydrogen atoms.

1.     Saturated fats promote heart disease and, because they are calorie-dense (like all fats) but lack the metabolic benefits of n-3 fats and CLA, they promote weight gain.

2.     Small amounts of saturated fat tends to come from the same foods that contain CLA and ALA and therefore, saturated fat intake cannot not be entirely avoided and should not be of concern to most people.

3.     Animal products are significant sources of saturated fats. Grass-fed beef and dairy have saturated fat but also contain relatively high levels of CLA and ALA. Therefore, the consumption of some red meat and dairy is clearly acceptable and probably beneficial.

                                        iii.    Cholesterol: Sterols are a class of fats that play very important roles in human health, both good and bad. Cholesterol is the most important of these. Generally sterols are not calorically significant nor do they appear (at least yet) to be causative of obesity. Cholesterol is of course a contributor to heart disease and therefore, all other issues being equal, is best avoided. Unfortunately this isn't always possible because some sources of good fat are also sources of cholesterol. Below are a few important facts about cholesterol:

1.     Cholesterol is only found in animal tissue not plants. This is why plant products like margarine are labeled "Cholesterol-free". But, as described above, because all margarine used to and some margarine still does contain trans-fat, this can be very misleading. Furthermore, margarine lacks conjugated linoleic acid (see above); better contains it.

2.     Dietary cholesterol generally does not affect blood cholesterol levels as much as endogenous cholesterol does. Endogenous cholesterol is the cholesterol made by our liver. The amount of endogenous cholesterol produced by the liver is influenced by genetics and by the nature of the fats we consume (as discussed above). This is a VERY complex subject, but the bottom line is that cholesterol in food generally (depending upon amounts) raises blood cholesterol less than trans-fat or saturated fat. In other words, for this reason, and for reasons cited above, it clearly is better to consume butter than margarine.

3.     Cholesterol is a contributor to atherosclerosis (scarring of the arteries) that can lead to heart attack, stroke and death.

4.     Cholesterol is not the only contributor to heart attack risk. Smoking, obesity,  lack of exercise, genetics and chronic inflammation all play independent roles in heart attack risk. In other words, smokers with normal cholesterol levels are at higher risk for heart attack than non-smokers with normal cholesterol levels.

5.     As mentioned before, cholesterol in food does not appear to affect weight although weight certainly does affect blood cholesterol.

c.     Summary of Fats:

                                          i.    "GOOD" Fats for Weight Loss:

1.     "Conjugated Linoleic Acid" (CLA)

2.     N-3 or Omega-3 Fatty Acids

3.     Diacylglycerols

4.     Medium Chain Triglycerides

                                        ii.    DO eat THESE Fatty Foods:

1.     grass-fed dairy and meat in LIMITED amounts (these products still contain ample saturated fats)

2.     Fish, insect or greens-fed chicken eggs (Eggs labelled as 'highOmega 3')

3.     Oily deepwater fishes (or take a fish-oil supplement)

4.     Tree nuts in moderation

5.     Flax oil or flax seed

6.     Extra-virgin olive oil--in moderation

7.     Consider MCT oil as a replacement for other fats but be aware that it is expensive.

                                       iii.    "BAD" Fats for Weight Loss

1.     Man-made trans-fat: Basically a metabolic poison.

2.     Large amounts of n-6 fats like corn oil

3.     Saturated fats

4.     MUFAs and non-N-3 PUFAs are heart-healthy but probably promote weight gain in even moderate amounts

                                       iv.    Do NOT Eat (or at Least Drastically Limit) THESE Fatty Foods

1.     Grain-fed fatty red meat (very lean grain-fed red meat is acceptable)

2.     Grain-fed butter, cream and whole milk--1% and skim milk and all sugar-free yogurt is acceptable (the probiotic benefits of yogurt offset and risk from saturated fats)

3.     Most vegetable oils except in extreme moderation and except tree nut oils, flax oil and extra-virgin olive oil.

4.     Regular eggs

5.     Pork--unless VERY lean

6.     Peanuts

7.     Margarine

8.     Fried foods

 

 

 

 

2.     Carbohydrates: Starches, sugars, resistant starches and fiber

 

a.     Sugars: Sugars are small carbohydrates that dissolve in water and taste sweet. Sugars come in two forms:

                                          i.    Spotting hidden sugar in foods. Look out for any of these ingredients in food:

Ø  Corn sweetener

Ø  Corn syrup

Ø  High-fructose corn syrup

Ø  Dextrose

Ø  Fructose

Ø  Glucose

Ø  Lactose

Ø  Maltose

Ø  Sucrose

Ø  Honey

Ø  Sugar

Ø  Brown sugar

Ø  Invert sugar

Ø  Molasses

Ø  Malt syrup

Ø  Syrup

Ø  Evaporated cane juice.

                                         ii.    Simple Sugars: There are three main simple sugars that are relevant to human nutrition

1.     Glucose

a.     Also called "Blood Sugar", glucose is the "Sugar of Life". Unfortunately, it can also be the sugar of "death" when excessive levels of this sugar accumulate in the blood.

b.    "Glycemic Index" is determined by studying how fast certain foods cause blood glucose levels to rise.

c.     Glucose is rarely found as a pure sugar in nature. It is found in some fruits, but usually along with other sugars like fructose and sucrose.

d.    All starch (potato, wheat, rice…ALL of it) is composed of nothing except glucose, but in starch, the glucose is not "free". Instead, starch is VERY long chains of glucose molecules all chemically bound together. However, digestion of starch always produces only one simple sugar: glucose. This is why starches are so important to glycemic index.

e.     Wood and bran are also made of long chains of glucose called "cellulose", but the chains cannot be broken by humans or even by the bacteria in our gut. Therefore cellulose has zero nutritional calories and is more commonly called insoluble fiber or "roughage". Just FYI, cellulose certainly DOES have "chemical calories" as evidenced by the fact that wood gives off a lot of heat when it burns (remember that calories are just energy or heat).

f.     Old-fashioned Karo corn-syrup is mostly pure glucose.

2.     Fructose:

a.     Fructose is also often called "fruit sugar" because much of the sweet taste of some fruits comes from fructose.

b.    Most fruits contain other sugars besides fructose.

c.     All fruits (except watermelon) contain huge amounts of fiber that "dilute" fructose so much that they are absolutely safe to eat in whole-fruit form. Fruit juices may NOT be so safe or healthy.

d.    Fructose is currently a controversial sugar. Some (but not all) scientific studies in animals and people suggest that excess fructose consumption may be harmful to human health and may specifically increase risk for obesity, metabolic syndrome and type-2 diabetes.

e.     High fructose corn syrup (HFCS) is a VERY controversial sweetener today.  As the name suggests, HFCS contains a lot of fructose (relative to old-fashioned Karo corn syrup-which is essentially pure glucose).

                                                                                          i.    There are several popular HFCS mixtures:

1.     HCFS 42: Used in baked goods., This contains 42% fructose, 53% glucose and 5% "other" sugars, mostly maltodextrins

2.     HFCS 55: Used in soft-drinks: 55% Fructose

3.     HCFS 90: 90% fructose

4.     HCFS is used in so many foods because it is sweeter and cheaper than sucrose (table sugar).

5.     HFCS was "invented"--actually the process to make it was invented-- in the 1970's and the operation became commercially viable in the mid-1980s

6.     There is an eerie correlation between the introduction of HFCS-55 in soft-drinks in the USA in the mid-1980's and the obesity epidemic in the USA, especially the epidemic of obesity in children.

7.     The corn industry---basically Archer Daniels Midland Corporation, Cargill and a few other conglomerates--- is spending a lot of money to convince the American public that HFCS is "Corn Sugar" and is a "Natural" product. The problem is that the manufacture of HFCS is about as industrial and non-natural as any in the food industry.

8.     Regardless of the possible problems that may be caused by fructose, HFCS may be contaminated with heavy metals because the product is often stored for long periods of time in railroad tanker cars whose stainless-steel welds contain dangerous heavy metals like cadmium that may leech into the HFCS stored within.

9.     I personally think that it is wise to avoidHFCS

                                                                                         ii.    Pure crystalline fructose is a "low-glycemic" sugar, but it is important to understand why: "Glycemic Index" is a measure of how fast blood-glucose levels rise after consumption of a food. Fructose and glucose are different molecules. If one were to imagine a "frycemic index" that measure the effect of foods upon blood-fructose levels, then fructose would be very high on the "frycemic index".

                                                                                        iii.   "Agave Syrup" is a low-glycemic sweetener (and is advertised as such) but it is nearly pure fructose and therefore carries all the potential harm that has thus far been discussed in relation to fructose.

                                                                                        iv.   Fructose is absorbed poorly by the human gut unless it is mixed with glucose. Certain proteins that move fructose from the gut to the blood stream require glucose to function.

                                                                                         v.   Fructose "malabsorbtion"---the inability of some people (perhaps most of us) to absorb pure fructose MAY (or may not) be a cause of irritable bowel syndrome (IBS) and other digestive disorders

                                                                                        vi.   Sucrose (table sugar) is 50% fructose and therefore ultimately barely-less a source of potentially harmful fructose than HFCS-55.

                                                                                       vii.    Some studies strongly suggest that fructose promotes obesity in mice, rats and people because it causes resistance to a naturally produced, normal hormone called Leptin.

1.     Leptin is found in mice, rats, people and probably all mammals and leptin is produced by fat cells and leptin suppresses appetite.

2.     Given the fact that statement (1) above is true, leptin resistance should and does cause weight gain. Therefore, if fructose causes leptin resistance (and I think that it does), then fructose should cause obesity (and I think that it does).

3.     THEREFORE it is probably wise to limit fructose consumption. Small amounts from whole fruits are cleary fine (and even good for you), but fruit juices, sodas and sugary foods are NOT.

3.     Galactose:

a.     Galactose is mostly found in the dairy sugar called "lactose".

b.    Lactose, but not pure galactose is poorly-absorbed by some people and causes what is known as "lactose intolerance"

                                        iii.    Complex Sugars: Complex sugars are molecules that taste sweet, dissolve in water but are composed of two or more simple sugars that are chemically "chained' together together.

1.     Sucrose: table sugar

a.     Sucrose is a "disaccharide" (two simple sugars chemically bound together). Specifically, sucrose is made of one molecule of glucose and one molecule of fructose.

b.    Sucrose  is a "high-glycemic" food because half of the sucrose molecule is glucose and because that glucose (as well as the formerly attached fructose molecule) are rapidly released in the gut when sucrose is digested by an enzyme called "sucrase" found on the "brush border" of the cells of the small intestine.

c.     Sucrose is a rich source of fructose and therefore  may be harmful to weight and health for the same reason(s) that fructose (above) MAY be harmful to health.

d.    Sucrose is a strong promoter of tooth decay. Dental caries (cavities) were rare before sucrose became a staple of the human diet.

2.     Lactose:

a.     Lactose is found almost exclusively in dairy products. Especially cow's milk and whey (the liquid left-over after cheese-making).

b.    Lactose is a disaccharide composed of glucose and galactose.

c.     Lactose does not appear to be a contributor to weight gain (beyond the simple fact that it contains calories).

3.     Maltose and maltotriose & Maltodextrins:

a.     Beer and some energy drinks contain sugars that are two, three, four, five and longer chains of glucose molecules.

b.    Generally, the longer the chain (the greater the number of glucose "links" in the chain) the less sweet the compound  tastes.

c.     Maltose or "malt" or "malt sugar" is two glucose molecules chemically bound together.

d.    Maltotriose is three glucose molecules chemically bound together

e.     Maltose and maltotriose are actually HIGHER on the glycemic index than is pure glucose, probably because pure glucose delays gastric (stomach) emptying more than do these di and tri-saccharides.

b.    Starches: Starches are very long chains of glucose molecules that do NOT taste sweet and do NOT (generally) dissolve in water. Note that starches contain glucose ONLY and therefore are broken down by the body into glucose only. There is no clear transition from a small glucose sugar like maltotriose to a starch, but most starches are not several or even tens of glucose molecules-long; they are thousands or tens-of-thousands of glucose molecules-long.

c.     Fiber: Fiber is composed, generally, of long chains of glucose molecules that are chemically "chained" together in such a way that we cannot and our gut-bacteria cannot  (except for resistant starch) break them down. Fiber is classified into three forms:

                                          i.    Insoluble fiber (ISF)

1.     Insoluble fiber is "roughage", the fibrous, pulpy material found in green, leafy vegetables and in bran. Chemically, insoluble fiber is made mostly of cellulose, the same material that gives wood its strength.

2.     Insoluble fiber promotes health and weight loss:

a.     ISF has physical bulk that fills and distends the stomach creating fullness.

b.    ISF offers particles for health-promoting bacteria in the gut to grow upon.

                                        ii.    Soluble Fiber

1.     Soluble fiber isn't really fiber at all. It is material that dissolves in water and forms slippery or rubbery gels. Examples include fruit pectin, psyllium husk (Metamucil), guar gum and the soluble fiber in oats that make oatmeal slimy.

2.     Soluble fiber, like ISF, can promote fullness and regularity.

3.     Some soluble fiber (oat fiber) can bind-to bile-salts in the gut and thereby prevent them from being reabsorbed by the body. This can lower cholesterol levels.

                                        iii.    Resistant starches: These are very long chains of fructose--not glucose. The human gut cannot, by itself, digest resistant starches, but some bacteria found in the colon can. Because resistant starches can selectively promote the growth (in the colon) of bacteroidetes ("Good"{weight-loss-promoting} bacteria), resistant starches are also called "pre-biotic" nutrients.

1.     Inulin (NOT "insulin") is the most abundant pre-biotic or resistant starch in the human diet and is commonly found in garlic, artichoke, chicory root and Jerusalem artichoke

2.     Clinical and animal studies suggest that higher-inulin diets promote weight loss.

3.     Too much resistant starch in the diet causes gas.

 

3.     Protein:

a.     Properties of and Relevant Facts About Protein:

                                          i.    Proteins are the most structurally and chemically complex macronutrient.

                                         ii.    Protein contains about four calories per gram

                                        iii.    Unlike carbohydrate or fat, protein doesn't normally contribute its calories to energy storage in fat or glycogen. Rather, and as we shall see, protein helps maintain the body's structure and function.

1.     In fact, we have no way of storing protein. The body takes exactly what it needs from every meal and if there is an excess, only then is energy extracted for fat or glycogen storage.

2.     The corollary of this is that if we do not get high-quality protein on a regular basis, we can quickly develop deficiency.

                                        iv.    Protein has the highest thermic effect of any macronutrient (approximately 30%)

1.     Thermic effect of food is the percent of calories in  food that are burned off during and  shortly after eating it due to digestion, absorption and other factors that are less-well understood .

                                         v.    Protein has drug-like effects upon the human brain that generally suppress appetite and hunger.

1.     The amino acids phenylalanine, tyrosine and tryptophan are all "chemical precursors of neurotransmitters--brain chemicals-- that lower appetite.

                                        vi.    Protein has drug-like and hormone-like weight-loss effects outside the brain as well.

                                       vii.    Very high levels of protein intake clearly cause weight loss but are difficult to achieve

1.     Average American daily protein intake varies by age as shown below:

Am J Clin Nutr May 1, 2008 vol. 87 no. 5 1

 

Protein Intake

                                      viii.    Daily protein intake near 120 grams is the clear threshold for improved weight loss and reduced appetite.

                                        ix.    Excess protein gets metabolized into carbohydrate-like molecules, but at significant metabolic expense (ie excess protein contributes relatively little to dietary calories)

                                         x.    Excess protein also is metabolized into "nitrogenous" (nitrogen containing) waste products that must be filtered into urine by the kidneys. In healthy adults, this is easily handled, but no so in people suffering kidney disease. People with kidney disease should never attempt a high protein diet.

                                        xi.    Proteins are built-up from twenty-three different building blocks that are called amino acids.

1.     Essential amino acids cannot be produced by humans and therefore we must acquire them from the proteins that we eat. The essential amino acids are:

 

 

Essential

Amino Acid

Name(s)

Amount Needed

Daily as mg per

Kilogram of Body

Weight

mg per 70 kg

(~154 lbs)

mg per 100 kg

(~204 pounds)

Isoleucine

20

1400

2000

Leucine

39

2730

3900

Lysine

30

2100

3000

Methionine

Cysteine

10.4 + 4.1 (15 total)

1050

1500

Phenylalanine

+  Tyrosine

25 (total)

1750

2500

Threonine

15

1050

1500

Tryptophan

4

280

400

Valine

26

1820

2600

2.     Non-Essential Amino Acids: These are amino acids that CAN be produced by humans.

                                       xii.    Protein "Quality" is determined by the balance of essential AND non-essential amino acids provided.

1.     Some protein like collagen (gelatin) is low-quality because it lacks certain essential amino acids. In fact, a popular diet shake from the late 1970s called "The Cambridge Diet" killed many people because, although it was technically sufficient in protein, the protein was only gelatin and thus, over time, caused fatal amino deficiency.

2.     The highest quality proteins include milk and egg proteins. This isn't surprising since both are naturally used to nourish very young or embryonic animals.

3.     Adequate intake of essential amino acids can be challenging for "Vegan" vegetarians and special care must used to consume plants that contain all essential amino acids.

 

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