Low Carb Diet:

Liberal, Moderate and Strict

Is there such thing as too low? How many carbs should you be eating per day?

The name Low Carb, and even LCHF (Low Carb High Fat), is not specific to any one level of carbohydrates, fat or even protein. There is a wide range or spectrum. There are many dietary approaches within this Way Of Eating (WOE). In my opinion, the level of carbohydrate (and/or protein) restriction will vary depending mostly on the metabolic health of the patient/client.

People metabolically healthy and fit, may prefer a more liberal LCHF diet.

A strict (see below) LCHF aka Keto Diet is often recommended "therapeutically" for people with Metabolic concerns such as Diabetes, PCOS, Obesity and people with epilepsy. 

The Primal Diet is another commonly referred to LCHF dietary approach. Many people follow the Primal Diet as a lifestyle. Often referred to as a "paleolithic" or "primitive" way of eating. The general recommendations for the Primal/Paleo Diet don't necessarily define the carbohydrate intake level or restriction. It is considered a liberal (see below)  "Low Carb" diet because it encourages the elimination of grains and added sugars. It does, however, encourage the ad lib consumption of "Whole Foods", including fruit and root vegetables, and may not be the most "therapeutic" for patients with Metabolic Concerns. 

Strict LCHF: < 20 g carbs/d
Moderate LCHF: 20-50 g carbs/d
Liberal LCHF: 50-100 g carbs/d