A Diet Overview ➤ What You Should Know & Watch Out For

balanced meal for weight loss

Lose as much weight as possible in a short time – that’s what a lot of people want to do. Some people try a diet to achieve this goal quickly. Many ask themselves at least one of the following questions:

The word “diet”…

…can describe a way of eating in which certain foods and/or amounts are restricted. Usually the goal is to reduce body weight. However, it is also possible to use a diet to support treatment for illnesses.  

What kinds of diets are there?

Diets can be divided into the following categories:

  • Low-carb diet: In this diet only 5 to 40% of the calories come from carbohydrates. Examples are the Atkins, Mayo, Paleo, Dukan, Montignac or Keto diet.
  • Low-fat diet: Here only 10 to 30% of the daily calories are consumed as fat. These include the Low-Fat 30, Ornish, TLC, and Macrobiotic diets.
  • High-protein diet: In this diet more than 15% of the calories come from protein, in some cases even more than 40%. The Dukan, Medifast, and Paleo diets are in this category.  
  • Balanced diet: This diet is usually made up of a mix of low-calorie foods that total a daily consumption between 850 and 1500 cal per day. The following diets fall in this group: Weight Watchers, Dash Diet, SlimFast, and the Zone Diet.
  • Low-calorie diet: Here you only eat about 800 cal per day. These are often meal replacement diets, where you mainly drink shakes. Examples of low-calorie diets include SlimFast, Cookie, Medifast, Nutrisystem, the Raw Food Diet, and the Fast Diet.
  • Intermittent fasting: There are almost no guidelines about what you should eat during intermittent fasting. One option here is to eat within an 8 hour period during the day and fast the remaining 16 hours. You can also eat as you normally do for 5 days and then basically fast (= eat less than 500 cal) for 2 days.

low calorie smoothie

How do diets work?

A calorie deficit is the key to losing weight. That means you need to burn more calories than you consume. Most of the diets listed above are based on this principle; calorie consumption is reduced to about 800 to 1500 cal per day.

Good to know:

Depending on physical activity, age, and gender, the body needs between 2000 and 3500 cal per day or even more. Use this calculator to determine your individual, daily calorie requirement:

Why can diets be dangerous?

Classic dietetics recommends a balanced ratio of the three macronutrients carbohydrates, protein, and fat. Our daily calories should be made up of 50 to 60% carbohydrates, 15 to 20% protein, and 25 to 30% fat.

But what happens when we diet? The recommended ratio shifts dramatically. In a low-carb diet, the calories from carbs can drop to a mere 5% in extreme cases.


Changing the recommended macronutrient ratio can cause changes to the endocrine system. Hormones like insulin have a lot of effects on our body and constant fluctuations in its concentration causes problems for our endocrine system. The effects of this are often unpredictable due to the complex biochemical interactions in our body.

What are the advantages of a diet?

Excess weight is often a risk factor for high blood pressure, diabetes mellitus type 2, cancer, cardiovascular diseases, metabolic diseases, or physical disabilities: weight loss combined with regular exercise reduces your risk of disease.

running in the city

What is the “best” diet?

Since everyone responds to diets differently, you can’t really say which one is the “best”.(1) Scientific studies show that diets adhering to the basic principles listed above lead to approximately the same results in weight loss.(2, 3)

Which diet should I choose? How much weight loss is healthy?

Decide on a diet, choose one that corresponds with your preferences and that you can maintain for a longer period of time. It’s important that you can integrate the diet in your daily life: if you like to eat animal products, you can try a low-carb diet. This diet includes milk, meat, cheese, eggs, and select plant-based foods like nuts and salad. Don’t pick an extreme diet: it may lead to faster weight loss, but often creates a yo-yo effect and the changes to your endocrine system mentioned above.

What science says about the yo-yo effect:

80% of people who go on a diet experience the yo-yo effect afterward. The only way to avoid this is by eating a balanced diet and getting regular exercise. The more often you cycle through losing and gaining weight, the higher your risk of developing diseases of modern society (e.g. heart and pulmonary diseases).(4)

If you want to lose weight in a healthy way and keep it off, it is recommended that you lose about 1 kg per week.

low carb foods

What should I be aware of when choosing a diet?

When you start a diet, heed the following advice:

  • Keep your weight loss at a moderate level for a longer period of time.
  • Start eating a balanced diet with low-calorie foods.
  • Supplement the change in your diet with regular exercise. At least 150 minutes of exercise per week is recommended, depending on your fitness goal. Start running or bodyweight training – lots of adidas Runtastic apps will help you get moving.

Summary: learn how to eat healthy

During the diet you should learn how to improve your general nutrition. The “healthy eating plate” provides a good guideline: half of your plate should be vegetables and fruit. One quarter should be whole-grain products like whole-grain bread or whole-grain pasta, and the other quarter should be high-protein products like fish, poultry, legumes, or nuts. Work on your nutrition and get enough exercise – you will see positive, lasting results.  



Dr. Otmar Höglinger Otmar is a professor of Biochemistry and head of the degree program Food Technology and Nutrition at the University of Applied Sciences Upper Austria. View all posts by Dr. Otmar Höglinger