Determining Body Fat Percentage

Dataset: Body fat prediction

Communtiy Author: Contip

Machine Learning powered data analysis can be performed quickly and efficiently by MindsDB to enable individuals to make accurate predictions for certain metrics based on a variety of associated values. MindsDB enables you to make predictions automatically using just SQL commands, all the ML workflow is automated, and abstracted as virtual “AI tables” in your database so you may start getting insights from forecasts right away. In this tutorial, we'll be using MindsDB and a MySQL database to predict body fat percentage based on several body part measurement criteria.

Pre-requisites

Before you start make sure that you've:

• Visted Getting Started Guide
• Visited Getting Started with Cloud
• Downloaded the dataset. The dataset being used for this tutorial. Get it from Kaggle.

Data Overview

For this tutorial, we'll be using the Body Fat Prediction dataset available at Kaggle. Each row represents one person and we'll train an ML model to help us predict an individual's body fat percentage using MindsDB. Below is a short description of each feature of the data:

• Density: Individual's body density as determined by underwater weighing (float)
• BodyFat: The individual's determined body fat percentage (float). This is what we want to predict
• Age: Age of the individual (int)
• Weight: Weight of the individual in pounds (float)
• Height: Height of the individual in inches (float)
• Neck: Circumference of the individual's neck in cm (float)
• Chest: Circumference of the individual's chest in cm (float)
• Abdomen: Circumference of the individual's abdomen in cm (float)
• Hip: Circumference of the individual's hips in cm (float)
• Thigh: Circumference of the individual's thigh in cm (float)
• Knee: Circumference of the individual's knee in cm (float)
• Ankle: Circumference of the individual's ankle in cm (float)
• Biceps: Circumference of the individual's biceps in cm (float)
• Forearm: Circumference of the individual's forearm in cm (float)
• Wrist: Circumference of the individual's wrist in cm (float)

Add data to MindsDB GUI

MindsDB has a functionality to uploud your data file directly via the GUI where you can immediately query the data and create a machine learning model.

The following is the steps to upload your data directly to MindsDB:

• Access the MindsDB GUI via cloud or local via the URL 127.0.0.1:47334/.
• Select the button Add data or select the plug icon on the left side bar.
• The page will navigate to 'Select your data source'. Select the option 'Files'.

• Select the tab under 'Import a file'. Please note the dataset files should not exceed the maximum size limit which is 10MB.
• Provide a name for the data file which will be saved as a table.

Once you have successfully uploaded the file, you can query the data from the files table to ensure the information pulls through.

Run the following syntax:

SELECT *
FROM files.bodyfat
LIMIT 10;

Once you have confirmed the file has successfully uploaded and the data can be retrieved, we can move on to creating a predictor.

Create and train a machine learning model.

With the CREATE PREDICTOR statement, we can create a machine learning model:

CREATE PREDICTOR mindsdb.predictor_name
FROM files 
        (SELECT column_name, column_name2 FROM file_name)
PREDICT column_name;

The required values that we need to provide are: ​ - predictor_name (string): The name of the model - integration_name (string): The name of the connection to your database. - column_name (string): The feature you want to predict.

For our case, we'll enter the following syntax:

CREATE PREDICTOR bodyfat_predictor
FROM files
        (SELECT * FROM bodyfat)
PREDICT Bodyfat;

Select the Run button or select Shift+Enter to run the syntax. Once is is successful you will receive a message in the console 'Query successfully completed'.

You should see output similar to the following:

At this point, the predictor will immediately begin training. Check the status of the training by entering the command:

SELECT *
FROM mindsdb.predictors
WHERE name='bodyfat_predictor';

When complete, you should see output similar to the following:

As you can see, the predictor training has been completed with an accuracy of approximately 99%. At this point, you have successfully trained an ML model for our Body Fat Prediction dataset!

Using SQL Commands to Make Predictions

Now, we can query the model and make predictions based on our input data by using SQL statements.

Let's imagine an individual aged 25, with a body density of 1.08, a weight of 170lb, a height of 70in, a neck circumference of 38.1cm, a chest circumference of 103.5cm, an abdomen circumference of 85.4cm, a hip circumference of 102.2cm, a thigh circumference of 63.0cm, a knee circumference of 39.4cm, an ankle circumference of 22.8cm, a biceps circumference of 33.3cm, a forearm circumference of 28.7cm, and a wrist circumference of 18.3cm. We can predict this person's body fat percentage by issuing the following command:

SELECT BodyFat, BodyFat_confidence, BodyFat_explain 
FROM mindsdb.bodyfat_predictor 
WHERE Density=1.08
AND Age=25
AND Weight=170
AND Height=70
AND Neck=38.1
AND Chest=103.5
AND Abdomen=85.4
AND Hip=102.2
AND Thigh=63.0
AND Knee=39.4
AND Ankle=22.8
AND Biceps=33.3
AND Forearm=28.7
AND Wrist=18.3;

This should return output similar to:

As you can see, with around 99% confidence, MindsDB predicted the body fat percentage for this individual at 8.97%. You can at this point feel free to alter the prospective individual's bodypart measurement parameters and make additional prediction queries if you'd like.

Making Batch Predictions using the JOIN syntax

The above example showed how to make predictions for a single individual's bodyfat, but what if you had a table of bodypart measurements for a number of individuals, and wanted to make predictions for them all? This is possible using the JOIN command, which allows for the combining of rows from a database table and the prediction model table on a related column.

The basic syntax to use the JOIN syntax is:

SELECT t.column_name1, t.column_name2
FROM integration_name.table AS t 
JOIN mindsdb.predictor_name AS p
WHERE t.column_name IN (value1, value2, ...);

For our purposes, we'll re-use the original data set, taking the Age, Density, Weight, Height, Neck circumference, Chest circumference, Abdomen circumference, and Hip circumference fields. We'll also include the original BodyFat percentage to compare our predicted values against the originals. Execute the following command:

SELECT t.Age, t.Density, t.Weight, t.Height, t.Neck,
       t.Chest, t.Abdomen, t.Hip, t.BodyFat, p.BodyFat AS predicted_BodyFat
FROM bodyfat_integration.bodyfat AS t
JOIN mindsdb.bodyfat_predictor AS p
LIMIT 5;

This should return an output table similar to the following:

As you can see, a prediction has been generated for each row in the input table. Additionally, our predicted bodyfat percentages align closely with the original values! Note that even though we chose only to display the Age, Density, Weight, Height, Neck, Chest, Abdomen, and Hip measurements in this example, the predicted_BodyFat field was determined by taking into consideration all of the data fields in the original bodyfat table (as this table was JOINed with the bodyfat_predictor table, from which we selected the specified fields). In order to make predictions based ONLY on the specified fields, we would have to create a new table containing only those fields, and JOIN that with the bodyfat_predictor table!

You are now done with the tutorial! 🎉

Please feel free to try it yourself. Sign up for a free MindsDB account to get up and running in 5 minutes, and if you need any help, feel free to ask in Slack or Github.

For more tutorials like this check out MindsDB documentation.