Best fit for Life diet health

In short: fit for life diet

Food choicesLittle variety
In practiceRelatively easy in the short term, difficult in the long term
WarningContraindicated in children, pregnant women, nursing mothers, the elderly and people with underweight.Yo-yo effectHypoglycemiaPossible deficiencies in protein, zinc, iron, calcium and vitamin D. 
Best fit for Life diet health

The origins

In the 1970s, the creator of this diet, Harvey Diamond, was disillusioned with weight loss. He was unable to lose weight sustainably. Under the guidance of a healthy friend, he began to follow the principles of natural hygiene , a holistic approach to health that seeks to restore the body to its self-healing power.

A month after changing his diet and lifestyle, Harvey Diamond lost 25 extra pounds. Suddenly, he regained a lot of energy and a new quality of life.

Convinced, he decided to devote his life to the study and promotion of natural hygiene. His first book, titled Fit for Live, appeared in 1985.

fit for life diet is one of the most popular diets of the last decades: 12 million copies of the first book have been sold worldwide. This diet is based on the principles of natural hygiene and draws heavily on the split diet of Dr.  William Hay and the food combination diet of Herbert M. Shelton.

The main principles


  • Losing weight.
  • Eliminate toxins.
  • Increase your vital energy.
  • Prevent disease and obesity.

The main lines

The Fit for Life diet is based on the principles of natural hygiene according to which the human body is able to purify, heal and maintain itself 1 . Thus, by eating in a way that respects the natural functioning of the body, we can prevent disease and obesity.

What matters is not so much what we eat, but rather how and when we eat it.

As part of this diet, we recommend that you avoid consuming too many food groups (meat and substitutes, fruits and vegetables, grain products, etc.) at the same time. For example, it is recommended to consume only fruits and fruit juices from 4 a.m. to noon to respect the body’s waste elimination cycle.

It is suggested to consume 70% foods with high water content (fruits, vegetables, fresh juices) and 30% “concentrated” foods (meat, poultry, fish, eggs, dairy products, legumes, nuts, seeds, products. cereals). Half of these foods should be raw and the other half cooked.

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Fit for life diet Basics

  • Fruits are eaten on an empty stomach only (20 to 30 minutes before a meal or 2 to 4 hours after).
  • “Concentrated” foods (meat, poultry, fish, eggs, legumes, nuts, seeds, grain products) are eaten only with vegetables and sprouts.
  • We limit ourselves to a single “concentrated” food per meal.
  • Food is ingested according to the body’s cycles.
 The three cycles of the organism 1  From 4 am to noon: the cycle of elimination of waste from the body.  Noon to 8 p.m .: consumption cycle (ingestion and digestion).  From 8 p.m. to 4 a.m.: assimilation cycle (absorption and use). 
Morning: Fresh fruit and fruit juice lunch: Fresh vegetable juice and salads
Steamed vegetables, peanuts, and raw seeds
Seeds, bread, potatoes, and purses evening meal (before 8 p.m.): Meat, chicken, fish, dairy products

Other tips:

  • Listen to the needs and desires of his body.
  • Don’t let yourself be too hungry.
  • If you are hungry in the morning, take bananas, because they are filling fruits.
  • Eat melons before other fruits, as they digest very quickly.
  • It is important to make the juices very salty before swallowing them.
  • Avoid excess raw onion and garlic. By stimulating the taste buds, they make you want to eat foods that are heavier to digest.
  • If you reduce your intake of dairy products, you replace them with nuts or seeds.
  • Do not eat meat more than once a day and prefer organic meat.
  • Milk should absolutely be drunk unaccompanied.
  • Greatly reduce the consumption of meat, eggs, dairy products, coffee and alcohol. They would provide more disadvantages than benefits.
Foods to avoid canned foods dried fruits if you want to lose weight foods containing chemical additives or preservative vinegar in salads, replace it with lemon juice fizzy drinks
fit for life diet

Mechanisms of action


Digestion is the physiological process that requires the greatest amount of energy. It should therefore be facilitated by following the right food combinations.

When taken with a meal, fruits ferment in the stomach because they stay there too long with other foods. This is the reason why they absolutely must be eaten on an empty stomach.

The body cannot digest more than one “concentrated” food at a time. The digestion of foods rich in protein requires an acidic environment while that of foods rich in carbohydrates or carbohydrates an alkaline environment. By consuming foods rich in protein (poultry, fish, etc.) along with foods rich in carbohydrates (bread, fruit, etc.), the environment becomes neutral.

Result: digestion is slow and incomplete. Incomplete digestion causes putrefaction and fermentation as well as poor waste disposal. We are also exposed to storing more what we eat as fat.

Also, the Fit for Life diet increases the vital energy that we have. This energy allows a better use of what we eat and a better elimination of waste.

The body is made up of 70% water. So it makes sense to eat 70% of foods with high water content to help eliminate waste and thus prevent weight gain and disease.


It is well shown that we can digest a mixture of macronutrients (proteins, carbohydrates, fats) with each meal 2. It is even better to combine them in order to increase our energy level and help in the absorption of certain nutrients. In addition, most foods naturally contain more than one macronutrient 2.

Rather, the fermentation and putrefaction of food comes from insufficient chewing, overcooked food, food intolerance or overly large meals.

There is no scientific evidence to support the hypothesis that the body burns calories more easily when it consumes them following certain food combinations.

Typical one-day menu

Morning meal
A large glass of fresh juice (1 to 2 cups, 250 ml to 500 ml)Multiple and varied fruits
Fresh vegetable juice large salad with lentil sproutsWhole grain bread with butter
A large saladVegetable soupSeasoned chicken

Advantages and disadvantages

Satiety and well-being

You risk being hungry by following this diet, which limits your daily protein intake (meat, legumes, eggs, etc.). The abundance of fruits and vegetables can fill you up, but not for long.

This method may be suitable for people with slow digestion. However, it is not recommended to follow it long term because of the risk of nutrient deficiencies it causes.

A person with slow digestion should instead eat six small meals a day, rather than three large ones.

In practice

This method is relatively easy to follow at home, but less so outdoors. Restaurant meals can be very bland and poorly nourishing if the principles of this diet ( fit for life diet ) are followed. For example, if you opt for chicken, in the menu, you can only accompany it with vegetables. Sauces, bread, rice, pasta, cheese, wine and desserts should be discarded.

In restaurants and at home, restrictions on the composition of meals can lead to monotony.


Two studies have shown that, for the same calorie intake, a diet ( fit for life diet ) that respects food combinations such as fit for life diet does not induce greater weight loss than a balanced diet 3, 4. Not being able to combine different food groups makes meals rather monotonous and sometimes tasteless. We can therefore end up eating less, and therefore losing weight.


  • This diet ( fit for life diet ) can induce the yo-yo effect due to rapid weight loss.
  • For some, eating according to food combinations could cause hypoglycemia (low blood glucose levels).
  • The Fit for Life diet can lead to nutrient deficiencies. On the one hand, food combinations reduce the variety of foods that can be eaten at the same meal. On the other hand, several food groups such as dairy products, meat, eggs are not recommended.
  • Due to a low protein intake, the diet can lead to muscle wasting and deficiencies in iron, zinc, and vitamin B12.
  • Eating a few dairy products can cause calcium and vitamin D deficiencies.
  • This diet ( fit for life diet ) is contraindicated for children, pregnant and breastfeeding women, the elderly, and people who are underweight.

Her passion for writing and her educational background has assisted her substantially in writing quality content on topics related to health and wellness. In her free time, Dev loves to explore the world and the different flavors/cuisines it has to offer. Photography is another hobby she has developed of late.

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