Acetic acid – the main component of vinegar. Vinegar, as well as other acidic food components such as lemon and lime juice, lower the glycemic index of foods. There are also indications that acetic acid may temporarily increase body thermogenesis and fat oxidation (burning).

Acidophilus – a ’friendly’ strain of bacteria used to make yogurt and cheese. Acidophilus bacteria also live in the intestines and, among other benefits, strengthen the body’s immune system. There are indications that this bacteria may be helpful in the weight management process.

Adipocyte – a fat cell. After puberty, the number of fat cells stays stable. If excess weight is gained by an adult, fat cells increase in size by about fourfold before dividing and increasing the absolute number of fat cells in the body.

Adipose tissue – the fat cells in the body. Adipose tissue serves not only serves as an energy store; it also produces a number of hormones, such as oestrogen, leptin and adiponectin.

AGEs - advanced glycation endproducts, see under dietary AGEs

Amino acids – building blocks of proteins. Muscle, collagen, some hormones and other structures in the body are made of proteins.

Arginine - an amino acid, contained particularly in nuts. In studies, supplementing high-calorie diets with arginine reduced weight gain significantly, when compared to the non-supplemented control group.

Bifidus – a ’friendly’ strain of bacteria which inhabit the gut and are included in some fermented foods. Among other benefits, these bacteria can boost human immune responses.  There are recent indications that they may be helpful in the weight management process.

Bioavailability – the proportion of a food or a supplement that is absorbed and available for use by the body. Bioavailability shows a high variability from person to person, and depends on various factors. For example, ingesting 1g of calcium does not mean that 1g of calcium is available to the body; furthermore, calcium from dietary sources seems to be more accessible to the body than calcium from supplements. As another example, vitamin C positively influences the bioavailability of iron to the body. Casein (an amino acid in dairy) negatively influences the bioavailability of flavonoids. Many chemical compounds have low bioavailability because they break down quickly into other compounds when ingested or are not well absorbed by the body (e.g. resveratrol and curcumin). The issue of bioavailability makes the estimation of health or fat loss effects difficult.

BMR (Basic Metabolic Rate) - the quantity of energy used per day when the body is at complete rest. The main factors influencing BMR are: gender, weight, age, genetics, body composition and body temperature.

Calcium - the most abundant mineral in the human body. Not only it is present in bones or teeth, but is also involved in body processes e.g. in the contraction of muscles or in transport of hormones. From the perspective of weight management, dietary calcium may slightly hinder the absorption of fat from the intestine and favour fat oxidation in the body during the dieting phase, resulting in higher fat loss for people on a high dairy diet as opposed to a control group 

Carbohydrates - a food group used by the body for energy. While cellulose is also a carbohydrate, the human body does not have the enzyme to break it down and use it.

Chlorogenic acid – a chemical compound present in larger amounts in green coffee. It inhibits some of the glucose uptake by the body and slows down the release of glucose into the blood stream after a meal. Unfortunately, after the coffee roasting process, only small amounts of chlorogenic acid remain.

Dietary AGEs – advanced glycation end products, are chemical compounds in food, formed when a sugar molecule bonds to either a protein or a fat molecule. They are most often formed during high heat in the absence of water, like baking, frying or roasting. Browning is an indication of AGE formation. Intake of foods with high content of AGEs has been linked to insulin resistance. Fructose and galactose (milk sugar) react easier then other sugars to form dietary AGEs. 

Disaccharides – just one chemical bond away from most simple sugars (monosaccharides), disaccharides are simple carbohydrates. The best known disaccharides are lactose (milk sugar) and sucrose (table sugar). However, the number of bonds in a sugar or a carbohydrate is not linked to the glycemic index.

Enzymes - chemical compounds that enable certain chemical reactions in the body. Digestive enzymes are located in the mouth, the stomach and the lower digestive tract. They help the body break down food, enabling it to be absorbed; the lipase group breaks down fats; the carbohydrase group breaks down carbohydrates; the protease group breaks down proteins.

Essential fatty acids – a category of fats that the body requires for body processes, but cannot synthesise by itself. There are two types of essential fatty acids – omega 3 and omega 6. They both belong to the category of so-called ‘polyunsaturated fatty acids’. Today’s typical ‘Western’ diet is poor in omega 3 fats, as the food sources are limited, with flax seeds, walnuts, sardines, shrimp, salmon, soybeans tofu being the best.

Fatty acid oxidation – the use of dietary and body fat for energy (‘fat burning’).

Fatty acids – fats in the context of nutrition (there are also fatty acids which are not food)

Fibre – the indigestible part of plants. The typical ‘Western’ diet does not provide the recommended amount of 25g (0.9 oz) a day for females and 30g (1.1 oz) for males.

Flavonoids (bioflavonoids) – a subset of complex chemical compounds called polyphenols. They are found in many plants, and, among a number of health effects, seem to play a role in weight management. Several hundred different flavonoids have been identified, making research into their action on the human body difficult. Flavonoids are broadly classified as follows:

• Anthocyanidins – mainly in red, blue and purple berries, red and purple grapes,red wine
• Catechins – mainly in teas (particularly green), grapes, berries, apples, chocolate, cocoa
• Theaflavins – mainly in teas (black tea)
• Flavanones – mainly in citrus fruits and juices
• Flavonols – mainly in yellow onions, broccoli, apples, berries, tea
• Flavones – mainly in parsley, thyme, celery, chilli
• Isoflavones – mainly in soybeans, soy foods, legumes

Flavonoids may facilitate weight management efforts. Up to now, the effect has been proven for flavonoids contained in green tea, citrus fruits, apples and onions.

Fructose – a type of simple sugar (monosaccharide) which cannot be used by the body for energy directly, but must be metabolised by the liver first. There is growing evidence that the elevated consumption of fructose in recent decades is one of the underlying reasons for the obesity epidemic.

Ghrelin – an appetite-regulating hormone, produced by the stomach. It goes up before regular meal times and when we are hungry, and down when we have eaten.

Glucagon - a hormone produced by the pancreas that stimulates an increase in blood glucose levels. It has the opposite effect of the hormone insulin (also produced by the pancreas), which lowers blood glucose levels.

Glucose (dextrose) - a simple sugar (monosaccharide) that serves as the chief source of energy in the body. The body makes glucose from carbohydrates, either directly or from the ‘storage’ carbohydrate form glycogen (and, to a far lesser degree, from fat and proteins). Glucose is carried to each cell through the bloodstream with the help of insulin (as blood sugar). What we call (table) sugar has a slightly different chemical structure (a combination of glucose and fructose), a lower glycemic index (60) and another chemical name (sucrose).

Glycemic Index (GI) – ranking of the effect of carbohydrates consumption on blood sugar levels (taking into account the rapidity and the amount of blood sugar increase). Carbohydrates that break down quickly during digestion release glucose rapidly into the bloodstreamhave have a high GI; carbohydrates that break down more slowly, releasing glucose more gradually into the bloodstream have a lower GI (preferable for weight management). The glycemic index of a carbohydrate food can be lowered by concomitant intake of fat, protein, fibre, acidic food (such as vinegar, lemon juice, yogurt, red wine), by shorter cooking time (such as for pasta), lower maturation (such as for bananas and other fruits) or degree of grinding (for flour). Consumption of low-glycemic index foods has been systematically linked to delayed return of hunger, decreased subsequent food intake, and increased satiety when compared to high-glycemic index foods.

Glycemic load – the effect that a specific amount of carbohydrate-rich food has on raising blood sugar levels. It calculates the glycemic index of food multiplied by the total quantity (in g) of carbohydrates consumed.

Glycogen - one of the body’s two ways of storing energy – the other one being fat (adipose) tissue. Glycogen is a carbohydrate that is broken down into glucose when used by the body for fuel. It is stored in the liver and in the muscles. The body’s ability to store glycogen is rather limited when compared to its ability to store fat - altogether, an average female body can store somewhere around 1200kcal (300g/ 10oz) worth of glycogen – depending on the amount of muscle mass. The body uses glycogen first, in preference to fat stores, for energy. The first weight loss experienced at the beginning of high protein and low-carbohydrate diets is mainly through the depletion of glycogen stores and loss of the water that was bound to this glycogen. This weight loss can account for about 1.25kg/ 3lbs in a female, slightly more for a male. The concept of carbohydrate loading in sport means replenishing the glycogen stores to their maximum before a sporting performance of long duration, such as a long distance run.

Hormone - a chemical substance produced in the body that regulates the activity of body processes (such as reproduction, the sleep cycle etc). More than three dozen hormones are known today to influence the management of food intake and fat storage in the body, for example oestrogens, insulin, ghrelin, leptin, adinopectin, peptide YY, orexins, resistin and cholecystokynine. Most of these hormones have been discovered only in the past 20 years.

Insulin - a hormone that controls the level of glucose in the blood (blood sugar) and the transfer of glucose to cells to be used as energy.

Insulin resistance - a state in which body tissues have a lowered level of response (desensitisation) to insulin, a hormone secreted by the pancreas that helps to regulate the level of glucose (sugar) in the body. As a result, the body produces larger quantities of insulin to maintain normal levels of glucose in the blood.

Iron – a mineral necessary for a number of bodily functions, in particular for the transport of oxygen in the blood. However, while the nutrition science has traditionally focused on iron deficiency, today the possible positive correlation of elevated body iron stores (ferritin levels) with central obesity and insulin resistance is under examination. 

Lactic acid – lactic acid is formed by natural fermentation in products such as cheese, yogurt, soy sauce, sourdough and pickled vegetables. Lactic acid lowers the glycemic index of the food, a feature helpful in weight management

Lactose - sugar found in milk (a disaccharide consisting of glucose and galactose). The body uses the enzyme lactase to break down lactose into galactose and glucose. The genetic lack of lactase (such as in Asian populations) or the decrease in its production seen in older people is the cause of lactose intolerance. Bacteria used to produce fermented dairy (yogurt, mature cheese, buttermilk etc.) food lower significantly the lactose contents.

Leptin – a hormone produced by the fat cells that signals satiety to the brain. Leptin is involved in the body's ability to utilise fat stores as an energy source. 

Leptin resistance – similar to insulin resistance; high, sustained concentrations of leptin from the enlarged adipose stores in overweight people may result in leptin desensitisation. Thus, the pathway of leptin signalling is flawed, so that the body may not adequately react with the feeling of satiety subsequent to eating.

Lipids – fats (in the context of nutrition)

Magnesium -While the human body needs about the third of magnesium as compared to calcium, it is still a very important nutrient. Magnesium plays a supportive role in a large number of body processes. From the aspect of weight management, the significant supportive functions of magnesium are the regulation of blood sugar level, control of inflammatory processes and better control of stress hormones. Studies suggest that the intake of magnesium correlate inversely with central obesity and the metabolic syndrome. 350 mg should be the bioavailable daily intake for females, 430 mg for males The average ´Western´diet does not deliver the sufficient in magnesium. Food rich in magnesium are seeds, nuts, beans and dark grean, leafy vegetables, as well as some mineral waters.

Metabolism - in the context of nutrition, metabolism defines the breakdown of food into components useful to the body and their utilisation for energy, cell construction and the maintenance of bodily processes.

Monosaccharides – the simplest carbohydrates, consisting of a single sugar molecule. Glucose, fructose, and galactose are monosacharides.

Nature identical flavours – flavours which, although produced in a laboratory, have the same chemical structure (and properties) to those found in nature.

NEAT (non-exercise activity thermogenesis) - all energy that is used for spontaneous movement during the day: tapping one’s feet to music, fidgeting with one’s hands, pacing when on the phone or gesturing, amongst many others. Level of spontaneous movement varies from person to person and tend to decline with aging

Neuropeptide Y – a neurotransmitter, the levels of which significantly influence appetite – the higher the levels, the higher the food intake (except in anorexia nervosa patients). Repeated stress and a high-fat, high-sugar diet increase the release of this neurotransmitter.

Neurotransmitter - a chemical through which a nerve cell communicates with other cells. It is, therefore, similar to hormones in its actions. In weight management, the neurotransmitters neuropeptide Y, dopamine, serotonin and norepinephrine (= noradrenaline) play the most significant roles.

Omega 3 fatty acids - one of two types of essential fatty acids - fats that the body needs for functioning and cannot produce by itself. (The other type are omega 6 fatty acids). The typical ‘Western’ diet is deficient in omega-3 fats,as the number of food sources with relevant quantities is limited to flax seeds, walnuts, sardines, shrimp, salmon, soybeans and tofu.The recommended daily amount is 3g.

Peptide YY – one of the hormones involved in appetite suppression. It is produced by the lower digestive tract. Consumption of food in general, and of protein in particular, enhances the levels of this hormone and, therefore, satiety levels.

Polyphenols – complex chemical compounds. Plants are the source of polyphenols in human nutrition. The most important subsets of polyphenols in nutrition are (bio)flavonoids and phenolic acids. Phenolic acids are usually present in the same foods as flavonoids (coffee and tea, berries, red wine, herbs, spices etc.). There are indications that polyphenols play a positive role in weight management.

Polysaccharides - carbohydrates, made up of numerous sugar molecules. Examples of polysaccharides include cellulose (fibre) and starch. Glucogen, the carbohydrate form that the body uses to store energy in the liver, is also a polysaccharide. However, just because a carbohydrate is a polysaccharide does not necessarily mean that it has a low GI.

Prebiotics – food ingredients that nourish bacteria in the digestive system. Most forms of dietary fibre exhibit some level of prebiotic effect. The top prebiotic foods are onions, legumes, whole wheat, garlic and bananas.

Probiotics – food or food supplements containing live bacteria the same, or similar to, those in the gut (mainly acidophilus and bifidus). Yogurt and other fermented dairy products such as kefir or laban, miso or sauerkraut are examples of probiotics.

Saccharides – older expression for carbohydrates.

Starches  (polysaccharides) – a type of carbohydrates consisting of large number of glucose molecules. The glycemic index of different starches varies significantly.

Sucrose – (table sugar) - a disaccharide, meaning that it consists of two simple sugar molecules – glucose and fructose. The glycemic index of table sugar is about 65, lower than most types of pastries, cereals, rice or fruit juice.

Sugar alcohol - sugar alcohols (polyols) are carbohydrates that are digested slowly or incompletely by the human digestive system. Although called alcohol, they have none of alcohol’s dietary properties. Common sugar alcohols are sorbitol, mannitol, maltitol, and xylitol. Xylitol in particular is suitable as a sugar replacement and as part of a weight management strategy

TEF – the thermic effect of food. In other words, the energy needed to digest food. TEF differs by ingredient. Protein stands out - about 25% of the initial energy value of protein is lost in digesting it - but only about 5% for carbohydrates and 3% for fat.  In practical terms, it means that 20% more of pure protein than carbohydrates can be consumed for the same final calorie contribution. 

Trans fatty acids (trans fats) - produced industrially through solidifying liquid oils (hydrogenation). Trans fats increase the shelf life of oils and are used in margarines, cookies, snack foods etc. The intake of trans fatty acids raises the risk of coronary heart disease, some cancers and central obesity. Their consumption should be avoided.

Visceral fat – fat in the abdominal region, which is not subcutaneous (under the skin) but grows around the organs. It has a negative effect on human health. High intensity exercise, low GI and low fructose diets are the most effective measures in preventing or reducing visceral fat.

Vitamin C - an essential nutrient, that cannot be produced by the human body, but needs to be consumed from food, mainly fruit and vegetables. Vitamin C is a water-soluble vitamin. It cannot be stored in the body and must therefore be replenished daily. In the area of weight management, adequate levels of vitamin C improve the use of fat for energy production. Insufficient blood levels of vitamin C were found to correlate with increased waist measurements and body fat.