There isn’t really a limit to how much you can have. You have a hypothetical minimum need for fat and protein. Once that’s fulfilled the rest of your energy can come from anywhere. 

As long as you’re not mainlining pure sugar your body will happily consume as many carbs as you feed it

1300 calories is way too low. So is the amount of carbs you are consuming. I am in my 50s and eat way more than you do. Use cronometer.com or something like it to calculate your caloric needs. You can eat as many carbs as you want. There is no limit. Carb counting is a joke. Also despite the whole low carb craze, carbs are not to be feared.

Since you are underweight right now, I would actually recommend gaining weight. The bottom end of the healthy weight range for your height is 56kg.

And based on your stats and activity level, I would estimate your maintenance calories to be somewhere around 2000. So for weight gain, I would start by aiming for around 2250 calories, and see how that goes. Depending on how active you actually are, you may need to increase your calories higher than that.

In terms of your carb intake, I would just focus on the calories first, and see where your carbs end up.

I am 37 F, H 174 cm, W 52 kg. I lead a pretty much active life style. I want to maintain my weight. I dropped from 58 kg to 54 kg after shifting to plant based life style. My TDEE is 1500 cal.

What is your age, sex, height, weight, and activity level? And are you currently trying to maintain your weight, or gain weight?

In general, there isn't really a "maximum", as long as you aren't exceeding your calorie needs.

If you want to increase your weight, eat avocado's as they have healthy fats and fibre.

That’s definitely a low daily intake. Nuts/seeds/avocado are easier since they’re calorie dense in smaller quantities but if you would rather gets calories from fruit or other carbs do that


Smoothies are easy and a good way to add calories without feeling over full

You can eat unlimited carbs from whole food sources.

Thank you for this incredibly thorough post! <3

First lets consider what is "optimal" in terms or carb intake, how to adapt this to general use, some of the health benefits, and then consider weight maintenance/loss.

**Optimal**

In terms of optimal, lets go by the "[Diet of Kenyan Runners: A Scientific Look at the Diet of the World’s Fastest Runners](https://runnersconnect.net/diet-of-kenyan-runners/)", where the diet is "made up of mostly natural, whole foods". 

For these people, "76.5 percent of daily calories were consumed as carbohydrates", and it implies taking in "about 10.4 grams of carbohydrate per kilogram of body weight" as being optimal, which at 52 kg is around 520 grams of carbohydrate. Note their protein intake is "10.1 percent of calorie intake. That equals roughly 1.3 grams of protein per kilogram of body weight", and around 13.4% fat. 

In other words, roughly [80% carbs, 10% protein, 10% fat](https://www.drmcdougall.com/misc/2013nl/feb/pritikinpdf3.pdf).

**General Use**

This is for people doing a lot of exerci

Flax seed hides easily in oatmeal or smoothie. It has a gel like quality, unlike other seeds, and is really interesting for being a source of essential fatty acids. 1 tbsp. milled flax per day keeps the weight on

What is the total carb we can safely take in a day if we are following a high carb low fat diet? I take 180 g per day. My total calorie intake is around 1300 cal. I want to increase my calorie intake as I  lost significant amount of weight after shifting to  plant based diet. I would prefer to incorporate more carb rich food as I am not a big fan of nuts. 
Thanks

Total carbs intake per day