Here are some basic guidelines to follow if you want to burn fat:
1. DIET
Eat 4-6 small meals per day that consists of the right portions of good protein, complex carbs, and healthy fats.
Avoid high glycemic "bad" carbs as much as possible.

Sample Meal:

BREAKFAST
1/2 cup lowfat cottage cheese & 1/2 cup pineapples =or= 2 hardboiled eggwhites with 1 apple or grapes.

MID-MORNING SNACKS:
2-3 slices of turkey or chicken (whitemeat) & 2 slices of swiss cheese

LUNCH:
1 grilled chicken breast, or salmon fillet on a salad with lots of fresh veggies, =or= 2 cups steamed =or= stirfry green veggies =or= a salad with tuna (fresh or canned) or chicken on it with any olive oil vinegratte dressing.

MID-AFTERNOON SNACK:
1 Low fat Yogurt (any flavor)

DINNER:
6 OZ GRILLED CHICKEN OR FISH OR LEAN PORK LOIN USE NO SALT ADDED SEASONINGS OR MARINATED ONLY.....with 1 small plain baked potato =or= 1/2 cup brown rice

REASON: This will help to keep you from getting too hungry, will reduce your overall calories, and will keep your blood sugar regulated.

2. EXERCISE
Do interval training instead of long "same speed" cardio routines
Add lean muscle mass by doing total body strength training sessions 2-3 times per week. Do not just use the strength training machines at the gym.
REASON: To burn calories and increase your metabolism.Good luck and remember that persistence pays off

REWARD FOR DOING A GOOD JOB EACH WEEK:
YOU CAN HAVE ONE(1) CHEAT MEAL A WEEK....EAT WHATEVER YOU LIKE. THEN BACK TO YOUR ROUTINE.....REMEMBER THERE IS NO SHORT CUT OF LOSING WEIGHT......EXERCISE 2-3 TIMES A WEEK IS A MUST...NO EXCEPTION.

AGAIN GOOD LUCK!!

Probably your mom is not eating enough protain and also doing the same routine is not doing any good either; she need to change here exercise routine and try not to eat the same food everyday. In addition take some supplement such as Vitamin B12. Don't try buying those junk diet supplement because it will never work instead save your money and hire a very good personal fitness trainer I highly recommend it.
Here are some basic guidelines to follow if you want to burn fat:
1. DIET
Eat 4-6 small meals per day that consists of the right portions of good protein, complex carbs, and healthy fats.
Avoid high glycemic "bad" carbs as much as possible.
Sample Meal:
BREAKFAST
1/2 cup lowfat cottage cheese & 1/2 cup pineapples =or= 2 hardboiled eggwhites with 1 apple or grapes.
MID-MORNING SNACKS:
2-3 slices of turkey or chicken (whitemeat) & 2 slices of swiss cheese
LUNCH:
1 grilled chicken breast, or salmon fillet on a salad with lots of fresh veggies, =or= 2 cups steamed =or= stirfry green veggies =or= a salad with tuna (fresh or canned) or chicken on it with any olive oil vinegratte dressing.
MID-AFTERNOON SNACK:
1 Low fat Yogurt (any flavor)
DINNER:
6 OZ GRILLED CHICKEN OR FISH OR LEAN PORK LOIN USE NO SALT ADDED SEASONINGS OR MARINATED ONLY.....with 1 small plain baked potato =or= 1/2 cup brown rice

Drink lots of water.....YOU CAN HAVE ONE CHEAT MEAL A WEEK....EAT WHATEVER YOU LIKE......REMEMBER THERE IS NO SHORT CUT OF LOSING WEIGHT......EXERCISE 2-3 TIMES A WEEK IS A MUST...NO EXCEPTION.

AGAIN: ONE CHEAT MEAL A WEEK!!!!

REASON: This will help to keep you from getting too hungry, will reduce your overall calories, and will keep your blood sugar regulated.
2. EXERCISE
Do interval training instead of long "same speed" cardio routines
Add lean muscle mass by doing total body strength training sessions 2-3 times per week. Do not just use the strength training machines at the gym.
REASON: To burn calories and increase your metabolism.Good luck and remember that persistence pays off