Proper Nutrition: How It Should Be, What to Eat and What to Avoid

Proper Nutrition: How It Should Be, What to Eat and What to Avoid

Proper nutrition is directly and indirectly linked to a lower risk of discomfort, disease, disability and death, and to a greater expectation and quality of life .

Furthermore, respecting a balanced diet also allows you to be more physically fit and mentally efficient .

Not everyone, on the other hand, can understand what an “adequate” diet should look like . Healthy eating , in fact, requires some knowledge of notions that are anything but obvious.

It is in this regard that, in the following paragraphs, we will try to better understand what to eat and what to avoid in a balanced diet .

For fairness we immediately anticipate that the topics covered will not only be the result of bibliographic research – it will not therefore be the “usual” article on the Mediterranean Diet – but will also include the author’s personal reflections based on outpatient experience.

What Should Proper Nutrition Look Like?

We apologize in advance if the contents of this paragraph do not follow the ideology of some readers; it is not our intention to deny or discredit the currents of thought of others, but we simply intend to expose some important principles on correct nutrition.

Most of the time, moreover, one truth does not exclude the other, provided that one does not make the mistake of confusing knowledge with conviction .

Proper nutrition should be varied and include all food types

Any nutritional regime that tends to ” restrict the choice too much ” exposes more to nutritional deficiencies or surpluses or proves to be poorly sustainable in the long term.

We’re not just talking about monothematic diets – e.g. the classic bodybuilder’s diet based on grilled chicken and basmati rice – but also diets that include the total exclusion of certain food groups – eg. the raw food diet .

This does not mean that even these diets cannot be made balanced with meticulous management – preferably by a professional – and/or thanks to nutritional integration / supplementation ; but they are simply not the most reasonable choice .

A balanced diet should be balanced ” in itself ” and, no less, it should be possible to follow it indefinitely ” without any problem ” of a nature: nutritional, ecological, economic, social, ethical and respectful of personal tastes .

Which and How Many Nutrients in a Correct Diet?

The body needs all nutrients, not just the “essential” ones .

Essentiality means that the organism is not able to produce them autonomously; certainly not that one can do without the others.

Impossible to summarize in a few lines how to have the “guarantee” of introducing vitamins and minerals in the right quantities, especially considering that age, sex and other variables (female fertility, level and type of physical activity , geriatric decline, etc.) affect heavily on these parameters.

In this sense, the most useful advice is to vary your diet – see the next paragraph.

If, on the other hand, we talk about energy macronutrients , i.e. carbohydrates , proteins and fats, the situation changes slightly. They can in fact be used as an “indicator” of the overall nutritional balance – but obviously not for everything.

Carbohydrates in proper nutrition

Dietary carbohydrates serve primarily to supply glucose , the ” by definition” energy nutrient .

Since the central nervous system and red blood cells “function” mainly on glucose and require at least 120 grams per day (g/day), with a sedentary (not bedridden) level of physical activity, the share of dietary carbohydrates should be around 180 g / day (approximately 2.6 g / kg of physiological body weight , but in sportsmen it can even reach 3.0-3.2 g / kg).

Chronic carbohydrate deficiency can lead to an increase in ketogenesis (production of ketogenic bodies) and/or the onset of typical symptoms of hypoglycemia ( coldness , exhaustion , dizziness , asthenia , etc.). Ketogenesis, in the healthy subject, is compensated by renal excretion; it is (theoretically) not harmful.

The chronic excess of carbohydrates is often associated with a caloric surplus. This determines a positive caloric balance and a tendency to gain weight , especially if the food excess also includes too much fat. Furthermore, chronic excess of carbohydrates and calories tends to reduce insulin sensitivity , predisposing to insulin resistance and diabetes.

Attention! Obesity also lays the foundations for numerous metabolic disorders , for the increase in cardiovascular risk , for certain tumors, etc.

Protein in proper nutrition

Dietary proteins mainly have the function of providing proteinogenic amino acids , both essential and non-essential A part of these will become part of the body’s proteins, while another part will contribute to energy production ( neoglucogenesis and ketogenesis).

Generally speaking, a sedentary adult can “prevent” protein deficiency by assuming about 1.0 g/kg of physiological weight of protein – some say a little less, some say a little more – without needing to check the nutritional source – provided that is varied.

In healthy people, however, intakes of around 20% of total kilocalories are frequent . To illustrate, a 75 kg man who trains in the weight room 3 days a week, with a caloric requirement of around 2300, could “comfortably” consume 115 g / day of protein (1.5 g kg) – this is not advice , but an average statistical value found at the outpatient level .

Athletes obviously require more , especially those who practice strength activities ( from 1.6 g / kg up to over 2.0 g / kg, depending on the bibliographic source consulted); for more information, consult the dedicated article.

The requirement also increases in growing subjects , a little also in pregnant women and nurses , in the case of a low-calorie slimming diet – to compensate for catabolism – and in old age – due to malabsorption and anabolic resistance.

Protein deficiency or suboptimal levels can impair endogenous protein synthesis . The result, more often than not, is a reduction in muscle mass but not only. All other tissues, from skin to bone , are also compromised .

The protein excess , in the healthy person, (in theory) does not cause damage of any kind, but it is still not very intelligent. The excess amino acids are used for neoglucogenesis and ketogenesis; might as well eat carbohydrates.

That said, some healthy people but with “not too brilliant” kidney function can “respond badly” to excess protein , seeing an increase in kidney parameters such as, for example, creatinine . Most of the time, it is not a question of functional damage , but it is a question of “spies” that should not be ignored.

Fats in proper nutrition

Dietary fats provide fatty acids with an energy function , essential or very useful lipids, and allow the absorption of fat -soluble vitamins (vitamins: A, D, E, K) .

A balanced diet can include a fairly variable percentage of fat; let’s say that the optimal range is between 25-30% of kcal / tot (but not everyone agrees). Some are able to “feel good” even with 15%, while others are comfortable staying around 35%.

Even in the most extreme, low-fat diets, it is advisable not to go below 0.5 g/kg of physiological weight. Conversely, 40% may be way too much — unless you’re on a ketogenic diet .

Chronic fat deficiency is associated with insufficient intake of essential polyunsaturated fatty acids ( AGE ) omega 3 and omega 6 , semi-essential polyunsaturated omega 3 EPA and DHA , malabsorption of fat-soluble vitamins, constipation , etc.

Chronic excess of fat, especially when associated with excess carbohydrates, promotes positive caloric balance and consequent fat gain . Regardless of whether the fats introduced are “good or bad”, this can reduce insulin sensitivity and cause other metabolic pathologies.

An excess of saturated or hydrogenated (“bad”) fats , especially in the trans conformation , and in particular when combined with high levels of cholesterol , can alter cholesterol levels and predispose to atherosclerosis .

What to eat in a correct diet?

In practical terms, and without going into too much detail, a correct diet should mainly include foods of plant origin and, in smaller quantities but with the right level of quality , foods of animal origin.

Seasonal vegetables / greens

Sources of water, fiber , vit. C , folate , vit. A , vitamin K, vitamin E , minerals (especially potassium ), other antioxidants (especially polyphenols) and modest amounts of “good” fats, even essential ones. They should be eaten both raw, to maintain vitamin integrity, and cooked, for the prebiotic function that the fiber exerts on the intestinal microbiota .

Attention! Vegetables preserved in jars (particularly if in oil ) do not have the same properties as fresh or, at most, frozen ones . Any type of cooking “makes the difference” on nutritional losses and caloric enrichment (think of frying ).

Cereals , other starchy seeds and starchy legumes , and starchy tubers such as potato and yam

Primary sources of glucose, fibers, some also bring significant levels of proteins of medium biological value , antioxidants (especially polyphenols), many vitamins. of group B, magnesium , potassium, unsaturated fats and modest quantities of “good” fats, even essential ones (especially in the germ or embryo ).

Attention! Not all “processed” products can be included in this category. Furthermore, those suffering from irritable colon with a prevalence of diarrhea should remember to limit whole foods and the peels of legumes; conversely, constipated subjects should try to prefer the integral. It is important to remember that anyone who eats legumes and cereals tends to accumulate intestinal gas ; it’s not about intolerance or other conditions, it’s just normal.

Sour and sugary fruit in season (you eat what the area and the climate offer)

Sources of fructose (which participates in the overall energy load together with the previous group), of water, fibre, vit. C, folate, vit. A, vitamin K, vitamin And, minerals (especially potassium), other antioxidants (especially polyphenols) and modest amounts of “good” fats, even essential ones. It should not be considered on the same level as vegetables, because it contains much more sugar.

Attention! Preserved fruit does not maintain the same properties as fresh fruit – with the exception of the few products that can be frozen. Jams , canned products, etc. they do not hold the same properties.

Nuts and oily pulpy fruits and extraction oils

Prefer those rich in unsaturated fatty acids , which therefore produce liquid oils at room temperature ( oleic acid , alpha-linolenic acid and linoleic acid ). Nuts also contain proteins of medium biological value, fibres, various vitamins (especially vitamins E and group B) and important minerals ( calcium , selenium , etc.); however, the bioavailability of some minerals is limited.

Attention! Nuts and extracted oils contribute massively to the calorie intake of the diet even in very small portions.

Meat, land and water foods

Meat (including offal ) and fish (including crustaceans and molluscs ) are primary sources of high biological value proteins , vit. D (fish, liver ), many B vitamins (e.g. B12, which is not found in vegetables), iron , zinc , selenium, etc. They can be replaced by whole eggs and/or milk and derivatives.

Attention! Cured meats and sausages do not have the same properties as fresh meat. Furthermore, the choice of the latter should be made consciously. There is no point in eating only chicken and turkey breasts , because the rest of these animals cannot be wasted. The same goes for beef, of which the loin and tenderloin tend to be consumed mainly . We learn to eat “all” the animal, eventually managing the other sources of fat in the diet. If no suitable solution can be found, it means that the diet contains too much meat.

Milk and derivatives

Sources of high biological value proteins, B vitamins (especially B2 but not only), vit. A, calcium, phosphorus etc. They can be replaced by whole eggs and/or meat, land and water foods.

Attention! Fat and aged cheeses do not have the same properties as milk and yoghurt . They certainly contain calcium, phosphorus and high biological value proteins, but they are excessively caloric, rich in calories and sodium .

Whole eggs

Sources of high biological value proteins, essential polyunsaturated fats , iron and many other minerals and many vitamins (especially A, D and group B). They can be replaced by meat, earth and water foods and, in part, by milk and derivatives (not for vitamin D and iron).

Attention! More and more people consume more egg whites than yolks. This is conceptually wrong, because it is in the yolk that all the vitamins and minerals are concentrated. If you can’t find the right balance between the amount of eggs and your cholesterol intake , it means that your diet contains too many eggs.


Together with milk and fruit, but much more than these, it is the ultimate “natural” food which provides significant quantities of soluble sugars. If unpasteurized , it may contain some vitamins (especially B vitamins), minerals, and polyphenolic antioxidants .

Attention! Honey is to be used in the same way as sugar – towards which it can be advantageous, because it is less caloric, only in equal portions.

Other “interesting” foods

  • Algae : they can become a good food to include in the diet, because they are rich in essential omega 3 polyunsaturated fatty acids and iodine ;
  • Mushrooms: from yeasts to basidiomycetes (“classic mushroom”), mushrooms can be included in human nutrition by providing several advantages. The yeasts give rise to the fermentation, releasing various nutrients and improving the digestibility of the products; classic mushrooms, on the other hand, are one of the very few non-animal sources of vitamin D – even if the concentrations are not comparable.
  • Fermented foods, especially vegetables and legumes: they have a marked probiotic component, which makes them potentially useful in maintaining good intestinal bacterial flora , but also some residual vitamins from microbiological metabolism ;
  • Sprouted seeds : inserted regularly, they help to increase the supply of many vitamins;
  • Wild herbs and wild fruits: used as vegetables, herbs or ordinary fruit, wild products can offer great nutritional benefits. First of all, they are “always available” (think, in the case of vegetables, of dandelions and wild chicory); secondly, they usually have a more “concentrated” chemical composition than the cultivated products;
  • Comb or hive products: Bees produce not only honey, but also propolis . Royal jelly , however rich, may not be a “sustainable” product, because it represents the primary food for the queen bee – which, if deprived, may not survive.

Supplements and Nutritional Supplements: Are They Necessary?

Now, it is true that nutritional supplements are also widely consumed by omnivores; However:

  • this trick is not always right to be – most of the supplements are completely ineffective;
  • often the goal is to support extremely prolonged or intense physical training – think of minerals for marathon runners ;
  • sometimes the goal is to “optimize” a goal – think of creatine for bodybuilders;
  • in pathological or para-physiological cases, integration becomes a real necessity – think of essential amino acids or protein powders / protein- enriched foods intended for sarcopenic elderly people , or even probiotics for those complaining of dysbiosis ;
  • last but not least, some supplementation protocols have a prophylactic purpose – think of folic acid and iron in pregnant women, even omnivores.

It is different if the diet in question, instead of an occasional supplement, requires chronic integration – think of vitamin B12 for vegans , or maltodextrins taken in conjunction with physical exercise by those who follow low-carb diets .

What not to eat in a correct diet?

It will be a short chapter because, nowadays, everyone knows what they should avoid .

The only foods to “eliminate” are those so distant from nutritional balance that they cannot be contemplated even 1 or 2 times a week. Let’s just talk about junk foods . We postpone reading to the dedicated article.

We will now debunk some false myths which often undermine a diet which, otherwise, could be considered almost balanced – in practice, these are “common mistakes”.

  1. Carbohydrates make you fat, cause diabetes and should never be eaten in the evening: wrong. Overweight and metabolic diseases are the result of a sedentary lifestyle and hyper-nutrition. There are athletes who consume 3000 kcal a day, most of which from carbohydrates , and train “the right way”;
  2. Proteins are bad for the kidneys and liver: wrong. Excess can harm the sick or mono-kidney. Healthy people have nothing to fear, but reasonableness remains an indispensable attitude ;
  3. High-protein diets increase muscle mass : wrong. Proteins must not be missing but the “anabolic” boost is given by carbohydrates;
  4. Fats make you fat : wrong, as for carbohydrates;
  5. The diet must be rich in fiber : colon permitting. Those suffering from chronic diarrhea from irritable bowel should instead try to “resize” the fiber intake, especially in periods of acute episodes. This can be done by avoiding wholemeal products and removing the peel of legumes, but continuing to eat vegetables and fruit normally;
  6. Butter causes atherosclerosis: wrong . It may contribute only if responsible for a chronic excess of saturated fat in the diet, therefore hypercholesterolemia , and more often in the presence of other risk factors such as obesity, diabetes and hypertension ;
  7. The “good” fats should be taken as much as possible, they are so good: wrong. Good fats have a positive metabolic impact but, in addition to the fact that too many polyunsaturated fats could lead to undesirable effects, fats provide many calories. So, if in excess they can make you fat and still promote metabolic diseases;
  8. Meat causes cancer : wrong. It’s the cooking methods and the addition of certain additives to preserved meats that make them “problem” foods when eaten in excess;
  9. Salmon is a healthy food – there’s no reason to think so . Regardless of its origin, salmon is a fatty food and should be treated as such;
  10. Man is not designed to digest milk: it depends. This only applies to those who do not digest lactose ; those who succeed, on the other hand, have no contraindication;
  11. Eggs increase cholesterol: it depends. Especially how sensitive you are to dietary cholesterol and, no less, how much of it you eat. Up to 3 a week are also allowed for hypercholesterolaemics;
  12. An apple a day keeps the doctor away: wrong. There is no reason to believe it may have healing properties;
  13. Eating lots of fruit is good: wrong. Four apples make up the calories of a plate of pasta with tomato sauce ; an obese person should avoid this habit. A diabetic who consumes two bunches of grapes a day without correcting the rest of the diet has a very high probability of not improving in his disease or of worsening;
  14. Fruit should not be eaten with meals: wrong. In the healthy subject, what makes the difference is the dietary complex. In diabetics, it may be necessary to correct the overall glycemic load of the meal – e.g. reducing the weight of cereals or legumes;
  15. Vegetables have no calories: it depends on the vegetable in question. Let’s consider that a portion of cooked vegetables easily reaches 200 g, that we could consume 2 a day, and that those with a “greedy tooth for vegetables” even double that. The total is 800 g. It is good to know that 1 kg of broccoli provides 340 kcal, or the amount of energy of a plate of pasta with tomato sauce ;
  16. The wine makes blood and the beer increases the lactation of the nurse: wrong; but it is true that, taken occasionally, a glass or two can give you a few moments of happiness. Irony aside, there’s no need to argue further;
  17. Phosphorus improves memory capacity: wrong. There are no correlations;
  18. Too much salt causes hypertension. Depends. It is certainly not recommended for those who already suffer from hypertension and can favor it in sodium sensitive subjects. However, a person of normal weight and not sensitive or who does not have congenital problems can safely consume table salt normally;
  19. Sugar makes you fat and causes diabetes: wrong. It’s always the dose that makes the poison. If the diet is in overall balance, more simple sugars than normal do not create any problems, because the complex ones will be less;
  20. The more vitamins you take, the better: wrong. Especially for fat-soluble vitamins (A, D, E, K), excess can be very problematic. We advise caution in choosing any nutritional supplements .


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