Every now and then a reference to the Paleolithic diet, or more commonly known, the "Paleo Diet", will creep into conversation. This diet advocates the diet model of eating like cavemen did 10,000 years ago to achieve optimal health, lose weight and keep at bay disease. The diet appears to have gained popularity in recent years, as many of the recommendations appear to make sense and mirror some of the guidance advocated by national food-based guidelines. But is this primal diet the remedy to obtain sustained weight loss?
This article will appraise this trendy diet and investigate further what the science says. However, as a general rule, before embarking on any diet it is important to exercise some caution; always carry out some thorough research, also examining what the critics have to say. Weigh up the pros and cons prior to making an informed decision.
WHAT FOODS ARE ALLOWED ON THE PALEO DIET?
The Paleo diet promotes the Stone Age diet model in order to achieve optimal health. Foods that can be hunted, fished or gathered are permitted: grass-fed meat, fish, shellfish, poultry, eggs, vegetables, fruits, nuts, seeds, grass-fed butter and some oils (olive, walnut, flaxseed, macadamia, avocado and coconut). The Paleo diet highlights selecting meat from pasture-fed or sustainably raised animals.
WHAT FOODS ARE FORBIDDEN ON THE PALEO DIET?
The general rule of thumb is that if cavemen did not eat it, then you should not either. No grains are permitted (barley, wheat, corn, oats, and rice), no dairy (milk, yogurt, regular butter and cheese), no legumes (all beans, lentils, peas, peanuts and all peanut products, soybeans and soy products), starchy vegetables (potatoes), no refined sugar, no salt, no cured meats (cured ham, salami and sausages), no packaged or processed foods. Why? According to the Paleo proponents, our bodies are genetically predisposed to eating this way. They blame the agricultural revolution and the addition of grains, legumes and dairy to the human diet for the onset of chronic diseases, for example obesity, diabetes and heart disease.
WHAT ARE THE BENEFITS AND CONCERNS OF ADOPTING THIS LIFESTYLE?
Two benefits of the Paleo diet are that it eliminates the reliance on refined carbohydrates and is low in sugar. Furthermore, it helps to eliminate processed snack foods that are high in energy and nutrient-poor. On the contrary, whole grains and legumes, which are forbidden on primal diets, are an important source of fibre and nutrients, as well as being an eco-friendly source of plant-based protein. In addition, whole grains have been linked to improved health by reducing heart disease and cancer. Furthermore, recent evidence suggests that dairy may have a beneficial role to play in weight loss and reduced risk of cardiovascular disease.
The Paleo diet encourages inclusion of fruit and vegetables, which is in line with the majority of national food-based dietary guidelines. However, the over-reliance of the Paleo diet on meat could contribute to increased risk of cardiovascular disease due to the high levels of saturated fat often contained in meat. Furthermore, this is not aligned with national recommendations, which typically encourage the reduction of red meat consumption for better health.
Eliminating whole grains, legumes and dairy is not the remedy to curb disease and promote weight loss. On the contrary, it could potentially be risky. These foods are nutrient-rich as they contain important vitamins and minerals, including calcium. Eliminating entire food groups could lead to nutrient deficiencies unless they are supplemented.
The advocating of coconut oil is controversial as it is exceedingly high in saturated fat - it is composed of about 85% saturated fatty acids. The scientific evidence shows a direct correlation of these types of saturated fatty acids with the raising of total cholesterol and LDL-cholesterol. As such, most national recommendations only recommend the occasional consumption of coconut oil or in small amounts as part of a healthy, balanced diet.
Although weight loss is often achieved with this diet, since fewer calories are being consumed, it is very difficult to maintain such an ultra-restrictive diet long-term; it could also promote yo-yo dieting which is detrimental for health. Weight will be regained as soon as “forbidden” foods are re-introduced into the diet.
We live in a society where it is almost impossible to eat exactly as our ancestors ate. Furthermore, it may be difficult to follow such a restrictive diet model due to the lack of variety and the need for supplementation of certain “excluded” nutrients. Moreover, the Paleo diet can be very expensive.
As a lasting note though, the majority of us would benefit from taking some Paleo “themes” and applying them to our eating habits: eat more fruit and vegetables, reduce refined carbohydrates, eat less sugar and try to buy sustainably raised meats, poultry and fish. These Paleo recommendations are consistent with widely accepted nutrition recommendations and could help to achieve improved health.
On food labels you will often come across the term "reference nutrient intakes" (RIs). These are helpful guidelines based on the approximate levels of nutrients and energy required for a normal individual to achieve a healthy, balanced diet each day.
"Reference intakes" (RIs) should not be considered as rigid targets as both energy and nutrient requirements can vary significantly between people: they are dependent on many factors, including age, sex and differing life stages. However, "RIs" do provide a useful indication of how much energy an average person needs and a rough guide of the correct proportions of nutrients that should make up a balanced diet.
**It is important to bear in mind that the term "reference intakes" (or "RIs") has replaced the term “guideline daily amounts” (“GDAs”), which used to appear on food labels. However, the principle behind these two terms remains exactly the same**.
Did you know that adult reference intakes are based on an average-sized woman?
Unless otherwise stated, RI values are based on an average-sized woman doing an average amount of exercise. The reason that an average woman's nutritional requirements are used as a reference is to cut the risk of people with lower energy requirements overeating. In addition, food manufacturers want to ensure that they communicate clear and consistent information on their labels.
As part of a healthy balanced diet, an adult's RIs for a day equate to:
For the major macronutrients, this should roughly correspond to the following daily energy proportions:
** Please note that the RI for total sugars is particularly high as it includes: sugars from milk, sugars contained in fruit and also added sugar**.
Many nutrition labels on food packaging provide information on the amount of each nutrient present e.g. fat, sugars and salt. This information can be expressed as a percentage of the reference intake for that nutrient. Percentage reference intakes (%RIs) can be given: by weight (per 100g), by volume (per 100ml) and/or by portion.
When percentage RIs are provided on a "per 100g/ml" basis, food manufacturers are obliged by law to include the statement "Reference intake of an average adult (8400kJ/2000kcal)" alongside.
Change in guidelines for levels of fat, saturated fat, sugars and salt
There are guidelines in place that elucidate if a food is high or low in fat, saturated fat ("saturates"), sugars or salt. These guidelines were reviewed and in some cases changed by the Department of Health (UK) in 2013. The updated figures are as follows:
High in fat: more than 17.5g of fat per 100g
Low in fat: 3g of fat or less per 100g
Saturated fat ("saturates")
High in saturated fat: more than 5g of saturated fat per 100g
Low in saturated fat: 1.5g of saturated fat or less per 100g
High in sugars: more than 22.5g of total sugars per 100g
Low in sugars: 5g of total sugars or less per 100g
The term "salt" is now used on food labels, rather than "sodium". The amount of salt is calculated by determining the total sodium in a product (both naturally occurring and from additives) and multiplying it by 2.5.
High in salt: more than 1.5g of salt per 100g
Low in salt: 0.3g of salt or less per 100g
If you are aiming to lose weight, your average daily energy requirement will be lower than if you want your weight to remain stable. The calorie checker tool embedded on the NHS website (a UK-based platform) is an excellent way to track how many calories there are in thousands of different foods and drinks. MyFitnessPal is also a very handy way to track food consumed over the course of the day and the attributed energy and nutrient contribution.
Green tea has been cultivated for centuries and was used in traditional Chinese medicine to treat a range of conditions from from headaches to depression.
SETTING THE SCENE
Green tea leaves are deemed to be richer in antioxidants than other types of tea because of the way they are processed. Antioxidants are substances that fight free radicals and have been shown to bring about a myriad of potential health benefits. Free radicals are harmful as they have the potential to cause damage to cells and alter genetic make-up (DNA); these manifestations have been implicated in inducing cancer, coronary heart disease and ageing. The mechanism by which antioxidants act is by preventing the formation of free radicals or by neutralising them, thus protecting the integrity of cells.
Tea Processing Methods
All varieties of tea (green, black and oolong) are produced from the Camellia sinensis plant using different processing methods. Green tea processing, as opposed to the other types of tea, does not involve fermentation; the fresh leaves from the plant are steamed to produce the green tea as we know it today. As green tea leaves do not undergo the fermentation process, they are reputed to contain a high concentration of polyphenols, also termed antioxidants.
Green tea contains B vitamins, folate (naturally occurring folic acid), manganese, potassium, magnesium, caffeine and other antioxidants, notably catechins. Green tea is alleged to boost weight loss, reduce cholesterol, combat cardiovascular disease, prevent cancer and Alzheimer's disease.
A CLOSER LOOK AT THE SCIENCE: Let's examine further whether this myriad of ascribed health claims to green tea are founded.
Green Tea and Cancer
As green tea is drunk widely across Asia, many correlate this with the observable trend of lower rates of cancer in this part of the world. But does this observation hold any truth? Some laboratory studies have shown that extracts from green tea can halt the growth of cancer cells. This could be explained by green tea's antioxidant properties. However, while these lab results hold promise, further evidence from human interventions is required to prove them.
The evidence from human studies is ambivalent. A meta-analysis - an overview of studies - published in 2014 suggested that green tea could reduce the risk of developing mouth cancers. Other clinical studies suggest that green tea consumption could reduce lung and bladder cancers. However, in 2009, the Cochrane Library published a review encompassing 51 studies, which involved over 1.6 million participants.
The authors from this high quality review concluded that the evidence of a link between green tea and cancer was weak and highly contradictory.
Green Tea and Weight Loss
It has been proposed that the antioxidants catechins in conjunction with caffeine contained in green tea could have a role in promoting the burning of calories, also referred to as speeding up the metabolism. In turn, this could promote weight loss. Green tea weight loss products such as herbal remedies are extracts of green tea which typically contain a higher concentration of catechins and caffeine compared to regular green tea.
A 2012 review examining 18 studies involving 1,945 participants found no significant effect of consuming green tea and weight loss promotion.
Green Tea and Cholesterol-Lowering Effects
There is increasing evidence that both green and black tea could have a beneficial role in preventing cardiovascular disease. A high quality review from 2013 found that daily consumption of green or black tea - as a drink or a capsule- could be involved in the lowering of cholesterol and blood pressure. Again, this is likely to be as a result of the antioxidant content. The authors of this review caution interpretation as the majority of the studies were short-term. As such, further long-term, high-quality studies are required to confirm this finding.
Furthermore, another review from 2011, found that green tea consumption enriched with antioxidant catechins could lead to small cholesterol reductions, which is a main risk factor in heart disease and stroke. Nevertheless, it remains unclear what levels of tea consumption would be required to bring about the observed health effects.
Green Tea and the Prevention or Progression of Dementia & Alzheimer's Disease
Evidence of a link between green tea and Alzheimer's disease is weak. A 2010 laboratory study using animal cells found that green tea enriched with antioxidant catechins protected against the nerve cell death indicative of dementia and Alzheimer's disease. However, whether these results can be reproduced in human studies remains to be seen.
As such, for the time science does not conclusively demonstrate a link between green tea consumption and Alzheimer's disease.
Sophie's professional opinion: In the Far East green tea has been regarded by many as the elixir for life, ascribing to it a plethora of beneficial health attributes. Although many of these are a bit far-fetched, the scientific evidence is pointing towards a potential role for the antioxidant components of green tea towards combating cardiovascular disease; this is probably due to green tea's cholesterol-lowering ability. However, this warrants stronger evidence from clinical trials to confirm these findings. The evidence for the preventative effects of the majority of other diseases, such as cancer, are weak or non-existent.
As such, tea appears safe to consume in moderation (approximately 3- 5 glasses a day). Remember that green tea contains caffeine and can act as a stimulant and may keep you awake if you drink it before going to bed!
When we talk about the correct storage of food, many of us have developed incorrect deeply rooted beliefs. These convictions need to be addressed head-on with sound science and a bit of common sense. For example, some of us are strongly convinced that storing tomatoes or coffee in the fridge will maintain and even enhance the flavours. However, these food "habits" that we have developed over time are often far from correct.
For instance, despite the fact that many ingredients should be stored in fresh, dry environments, they often should - at all costs - be kept away from the fridge. Garlic, for example, at overly cold temperatures will become soft and dry. Similarly, tomatoes will lose all their flavour if stored in the fridge.
If you would like some helpful tips on food preservation and to boost your general food-related knowledge, read on!
Tomatoes will lose all their flavour in the fridge. The cold air will prematurely end the maturation process; maturation is what gives tomatoes their recognisable flavour. The fridge will also alter the consistency and structural properties of the tomato. The cold will damage the membrane of the fruit, making it become powdery. It is better to store tomatoes in a tupperware in a cupboard or in a basket on the table.
Basil will shrivel up and perish if left in the fridge. Also, it will absorb all the flavours from the surrounding food. It is advisable to keep basil out in the open or in a glass of water (like you would normally take care of cut flowers). If you want to keep basil fresh for a long period of time, freeze it.
Potatoes that are kept at cold temperatures in the fridge will stimulate the chemical reaction that transforms starch into sugar more rapidly. This will also reflect in the flavour of the potato, which will become sweeter. Rather than storing potatoes in the fridge, store them in paper bag in a cool environment. If you don't have a pantry - the best place to store potatoes - keep them in a dark place, such as a cupboard. Paper bags work better than plastic as they allow more air to circulate, avoiding that the potato perishes quicker than at a normal rate.
If you put onions in the fridge, the humidity will cause them to become soft and mouldy. Keep them in a cool, dry location. Top tip: keep onions away from potatoes - if stored together they will deteriorate quicker!
If you want the avocado to ripen, definitely keep them away from the fridge. However, if you have purchased an avocado that is already quite ripe, you can pop it in the fridge if you do not wish to use it immediately.
Garlic will start to sprout buds if left in the fridge; it will also become chewy and eventually go mouldy. Keep garlic somewhere dry and cool.
In the fridge, fresh bread will quickly become dry. Unless you are not storing sliced pieces you wish to consume in a short space of time, it is better to keep the bread on the table or freezer. A trick is to keep bread wrapped up in a plastic bag so that it prevents the circulation of air. This ensures the bread remains fresher for longer. If the bread is stored in the freezer, it is also best to wrap it in a bag that traps the humidity. When it comes to defrosting the bread, it is advisable to completely defrost it slowly prior to eating.
8) Olive Oil
Olive oil should be stored in a dark, fresh place - but not in the fridge.
If you leave coffee in the fridge it will lose its flavour and, on the contrary, will pick up the odours from the food present in the fridge. It is recommended to store coffee in a cool, dark place, where it will maintain its naturally rich flavour and freshness.
There is no need to store honey in the fridge, as it will be delicious if it is simply kept tightly closed. Honey that is stored in the fridge runs the risk of becoming crystallised.
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Sophie Bruno is a Registered Dietitian living and working in Brussels (Belgium). Read Sophie's foodie blog which will enable you to learn, increase your knowledge & cultivate yourself in the field of nutrition & health directly from Brussels