Food and nutrition guidelines are a form of advice on diet and dietary patterns. This type of guidance is based on a systematic approach that is backed by scientific evidence. These guidelines are developed to help people make informed decisions about what to eat and how much to consume. In addition to providing general nutritional advice, they also provide specific information on specific foods and nutrient content.

In the US, a series of food and nutrition guidelines were published by the Dietary Guidelines for Americans (DGA) from 1980 to 2016. The DGA encouraged people to maintain “ideal weight” and advised them to consume less than 300 mg of cholesterol per day. However, the Dietary Guidelines for Americans conceded that there was no absolute answer to the question of ideal weight. Instead, the DGA suggested that most adults should keep their weight within 20 to 25 percent of their ideal body weight.

The DGA also recommended that adults drink plenty of water. It also advised adults to avoid foods high in fat and salt. Additionally, the Dietary Guidelines for Americans advised adults to limit saturated and trans fats. Aside from recommending that people limit intake of certain nutrients, the Dietary Guidelines for Americans encouraged people to eat a variety of foods. They also encouraged people to limit processed meats.

Developing and maintaining a healthy body weight is important in preventing diseases. For this reason, the Dietary Guidelines for Americans suggested that most adults should maintain their ideal weight and avoid excess weight. Moreover, the guidelines said that most adults should not consume more than 250 calories per day from fatty foods, and should eat at least 300 calories per day from nutrient-dense foods.

In the United States, the Dietary Guidelines for Americans (DGA) have been updated every five years since 1980. The DGA provides nutritional advice to both healthy and at-risk Americans. Some of the dietary recommendations are specific to people with chronic conditions, while others are general. As of 2015, the DGA includes three USDA Food Patterns: Healthy US-Style, Healthy Mediterranean Style and Healthy Vegetarian.

To develop dietary guidelines, governments should consider contextual factors. For example, if the government is concerned with health in a large city, then enacting nutrition standards may be a priority. Larger cities may have more resources available for developing and distributing healthier food and beverages. Similarly, a larger population may have greater demand for healthier foods.

During the development of dietary guidelines, countries should ensure that they follow systematic methods. Some of the key methods include systematically reviewing the evidence, grading recommendations, and managing conflicts of interest. There are several tools that can be used to assess the methodological rigor of dietary guidelines. One of these tools is the iCAHE Guideline Quality Checklist. Another is the Appraisal of Guidelines for Research & Evaluation (AGREE II) Instrument.

Detailed descriptions of the methods used to synthesise the evidence, grade recommendations, and manage COIs are provided in the study. Methods are classified into quantitative and consensus methods.