What characteristics does a healthy diet have to have?
There are many definitions of a healthy diet, but in general we can affirm that the Mediterranean diet pattern has been recognized as one of the healthiest worldwide since it has been shown to be associated with lower overall mortality, lower incidence of cardiovascular diseases, lower incidence of some cancers, improves intermediate phenotypes of plasma lipid concentrations, blood pressure, plasma glucose, markers of inflammation and has positive effects against some phenotypes of depression, cognitive impairment, etc. (Dinu et al, 2018; Dinu et al, 2020).
Therefore, among the different diets that have been proposed as healthy, taking into account the products and customs of our environment, we will focus on the Mediterranean diet. Although we consider the Mediterranean diet to be the healthiest, this consideration is carried out for the entire population. There will be cases of people with certain health problems, allergies, intolerances, or other conditions for whom the Mediterranean diet will not be the best option.
What are the characteristics of the Mediterranean diet?
It is a healthy pattern of food consumption, but there is no homogeneous definition of it and its name refers to the geographical area comprising the countries of the Mediterranean coast and citing the use of virgin olive oil as the main fat used in this diet (Serra-Majem et al, 2019).
In general, the Mediterranean diet is very rich in plant-based foods, including a high consumption of fruits and vegetables every day. It is also characterized by an abundant consumption of legumes and cereals (the least refined as possible are preferred). The proper consumption of nuts and the use of virgin olive oil for cooking and dressing food are recommended. As for animal products, their consumption is low and the consumption of fish and seafood and white meat is recommended, preferably red meat. The consumption of sweets and pastries is very low. Finally, moderate consumption of red wine is also recommended in some Mediterranean countries, however, this is the most controversial element of the Mediterranean diet pattern (Bach-Faig et al, 2011), since there are multiple studies that show the unfavorable effects of alcohol consumption and from a public health point of view its recommendation is not adequate. Therefore, in this Guide we will not refer to the consumption of wine in the Mediterranean diet pattern, making the recommendation of water consumption instead of sugary drinks and soft drinks.
In addition, a characteristic of the Mediterranean diet is the whole is better than the sum of its parts. In other words, although each of the characteristic foods of the Mediterranean diet has favourable effects on health, when considered together, their synergistic effect is enhanced, achieving a more protective effect on the pattern consumed (Corella et al, 2018). To provide guidance on the typical foods of the Mediterranean diet and their consumption, we will use the recommendations of the 14-point scale of adherence to the Mediterranean diet in which our research group has participated. It consists of 14 questions, which are scored with one point for each question. The higher the number of points obtained, the greater the adherence to the Mediterranean diet (Schröder et al, 2011). In accordance with this, the food recommendations and frequencies in a Mediterranean diet would be the following:
1-Frequent consumption of vegetable products, including vegetables. The consumption of vegetables, either fresh or cooked, should be at least twice a day. 2 or more servings (about 200 g/serving) of vegetables per day are recommended, at least one of them raw, for example salad. As vegetables are often eaten as a garnish, for the calculation of this adherence requirement, the consumption of vegetables as a garnish is counted as half a portion.
2-Take 3 or more pieces of fruit a day. For this calculation, natural fruit juices can be counted, although the three pieces of fruit cannot be replaced by juices. The simplest recommendation to meet this point is to have fruit as a dessert at main meals, and a piece at breakfast or snack.
3-Consume at least 3 servings (150 g/serving) of legumes (lentils, chickpeas, beans, etc.) a week.
4-Consume nuts at least 3 times a week. These nuts have to be consumed naturally without salt, with skin and without toasting or frying to maintain all the healthy characteristics. Even a daily consumption of nuts of 30g per day has shown its favorable effects in the prevention of different diseases.
5. Use virgin olive oil daily as the main fat in the diet to cook and dress food due to its composition not only in fatty acids but also in polyphenols and other bioactive components that have healthy properties. It is estimated at least 4 tablespoons a day for both cooking and dressing.
6- Eat fish and seafood frequently, at least 3 times a week. The rations established for this frequency are approximately 100-150 of fish or 4-5 pieces or 200 g of seafood.
7-Preferably consume chicken, turkey or rabbit meat instead of beef, pork, hamburgers or sausages (chicken meat: 1 piece or serving of 100-150 g).
8- Have a low consumption of red meat, hamburgers, sausages or sausages. It is recommended that the daily frequency of all this is less than 1 time a day (serving: 100-150 g)
9- Have a very low consumption of butter, margarine or cream consumed per day (single portion: 12 g) that is approximately less than once a day together.
10- Consume commercial pastries (not homemade) such as cookies, custards, sweets or cakes very infrequently (maximum 2 times a week).
11-Do not consume, or have a very low consumption (less than once a day) of sugary/carbonated drinks or soft drinks such as colas, other flavored soft drinks, tonics, bitters).
12- Consume water as the main drink at meals and throughout the day to ensure good hydration.
13-Choose whole grains instead of processed ones.
14-Use frequently (at least 2 times a week), the so-called sofrito (made with crushed tomato, garlic, onion or leek, made over low heat with olive oil) to prepare cooked vegetables, pasta, rice or other dishes that require dressing.
Currently, there is also a very high consumption of ultra-processed products, so it is recommended that the products that are part of these recommendations come from fresh products, minimizing the use of ultra-processed foods as much as possible.
What characteristics does a sustainable diet have to have?
In 2010, FAO published the document entitled "Sustainable diets and biodiversity: Directions and solutions for policy, research and action". It is a very extensive document, the complete content of which can be accessed free of charge on http://www.fao.org/3/i3004e/i3004e.pdf, in which, through its 310 pages, several chapters are presented focused on the analysis and development of the implication of each of the foods in the diet in sustainability and health from its different dimensions. It is not our objective now to delve into the aspects presented there, but we do recommend reading them to have a broad perspective. This document includes the consensus documents that were generated after the celebration of the International Scientific Symposium "Biodiversity and Sustainable Diets: United against Hunger", organized jointly by FAO and Biodiversity International, held at FAO, in Rome, from 3 to 5 November 2010. The Symposium was part of the official World Food Day program. This Symposium addressed the linkages between agriculture, biodiversity, nutrition, food production, food consumption and the environment. A consensus definition was reached at the Symposium The Symposium served as a platform for reaching a consensus definition of "sustainable diets".
According to this consensus, "sustainable diets" are those diets with a low level of environmental impacts that contribute to food and nutritional security and a healthy life for the present and future generations. Sustainable diets are protective and respectful of biodiversity and ecosystems, culturally acceptable, accessible, economically fair and affordable; nutritionally adequate, safe and healthy; while optimizing natural and human resources.
At this meeting, the Mediterranean diet was given as an example of a sustainable diet by several researchers providing concrete data. The evidence that supports this sustainability of the Mediterranean diet is the following: The Mediterranean diet is very varied, contributing to biodiversity; it adapts to the cultural traditions of the regions from which it originates; it has a high component of seasonality, using seasonal products; it also has a great variety in food preparation techniques and practices; In addition, it has a low environmental impact since few products of animal origin are consumed.
All these aspects of the Mediterranean diet can be calculated in terms of specific indicators, called footprints. There are multiple published studies in which these footprints are quantified, all of which are lower for the Mediterranean diet than for other types of diets (Berri, 2019; Serra-Majem et al, 2020). Moreover, the recent proposal for a planetary diet by the EAT-Lancet Commission (Willett et al, 2019), is very similar to the Mediterranean diet although it does not name it as such.
For many years, different types of footprints have been calculated to measure the environmental impacts of different products and organizations. However, there has been no homogeneity in either the denominations or the calculations. Currently, greater standardization is sought in these denominations and calculations and the European Union proposes the so-called Environmental Footprint, based on the life cycle. This overall environmental footprint can incorporate up to 14 different types of footprints including: climate footprint, water footprint, soil footprint, soil eutrophication footprint, mineral and fossil fuel consumption footprint, etc.
Among the different footprints that are already being calculated and are quite standardized, we highlight in the first place the so-called carbon footprint.
The carbon footprint measures the totality of greenhouse gases emitted directly or indirectly by an individual, product, organization or event. Although it's called a carbon footprint, it actually takes into account all the greenhouse gases that contribute to global warming, and then converts the individual results into carbon dioxide equivalents. However, a limitation of this footprint is that it does not take into account other environmental effects such as the water footprint, etc., so it would be more complete to calculate several footprints using the life cycle approximation mentioned above.
The carbon footprint is measured in carbon dioxide equivalent by mass and an inventory of greenhouse gas emissions is used following international recommendations and standards (such as ISO standards between ISO14064 and 14069). The calculation of the carbon footprint is not without complexity, thus, ISO 14064:2006 contains 3 parts and a set of criteria for the accounting and verification of greenhouse gases.
Another very relevant footprint in food production is the water footprint, which is defined as "the total volume of fresh water that is used to produce goods and services for an individual, a community or a company".
Another relevant footprint is the so-called "land use footprint" and is defined as the amount of land area needed to produce each product.
In addition to these general indicators that can be calculated for each food taking into account where it is produced, the resources needed for it, its storage, its transport, etc., other indicators have been proposed to evaluate the sustainability of diets in a more global way that also incorporates socio-cultural aspects. It is preferred to carry out an assessment of the 4 dimensions of sustainability, rather than focusing only on the indicators of the carbon footprint and the water footprint, among others.
The proposal of indicators to assess the sustainability of a diet that he proposes is proposed by consensus of several international expert researchers (Donini et al, 2016), is as follows
1. Plant/animal protein consumption rates;
2. Average energy sufficiency of the diet;
3. Diet energy density score;
4. Nutrient density of the diet, food quality;
5. Consumption/intake of fruits and vegetables;
6. Dietary Diversity Score, Environment
7. Composition and consumption of food biodiversity;
8. Local/regional food rate and seasonality;
9. Rate of production and/or consumption of organic food;
10. Physical activity/physical inactivity prevalence;
11. Adherence to the Mediterranean dietary pattern);
12. Statistics on diet-related morbidity and mortality;
13. Nutritional anthropometry).
Although this list is complex and is not usually fully evaluated, it is advisable to calculate not only the carbon footprints and water footprints when quantifying the sustainability of a diet or food. In addition to these footprints, other socio-cultural indicators must be considered. All this will be better reflected if the SDGs are applied in food sustainability in all its dimensions. Since the Conference of Rectors of Spanish Universities (CRUE), in May 2018, the commitment was made for universities to generate and transfer knowledge in accordance with the objectives of the 2030 Agenda for Sustainable Development, including the objectives and values of Sustainable Development in a transversal way in all their actions.
At the University of Valencia we have produced several Guides on the importance of the SDGs, applied to food and for its integration into healthy and sustainable food. Thus, in 2019 we prepared the so-called "Guide to the consumption of healthy and sustainable fruit". In it, in addition to highlighting the beneficial properties of the different types of fruit on health, we detailed the relevant aspects of sustainability of fruits, highlighting the importance of them being seasonal, organically produced and local fruits (you can access the complete Guide on the UV sustainability website). We have also prepared a "Guide to the healthy and sustainable container", where we present what characteristics the container itself must have in terms of composition (plastics, glass, etc.), transport, conservation to be healthier and more sustainable. We also review the characteristics of the food that is going to be consumed in the container, recommending the healthiest and most sustainable, also providing recipes for this. We discuss the SDGs that can be best met with a responsible use of the container, also minimizing the use of plastics, food waste, choosing sustainable local or fair trade food, depending on the characteristics and origin of each food. This Guide can also be found on the UV sustainability website.
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