The idea of "flat abs" is brilliant marketing, because it's not realistic for most people. That said, if you have a disproportionate amount of fat around the waistline, this can be a risk factor for diabetes, metabolic syndrome, PCOS and more.
No amount of planks or pilates will compensate if you are not eating well - that doesn't mean restriction and dieting (nasty cycle that will only make you feel awful!) but that you are aware of eating a decent serve of veggies (especially green), fruit (so many choices!), legumes, wholegrain carbs (love rye bread or wholegrain pasta) and lean protein (fish, skinless chicken, prawns, tofu).
This time of year it's tempting to overdo everything but try to keep your workout routine. Not just for the sake of your abs, but your sanity.
10 To 2
Lie on your back, pressing your whole spine into it.
Slightly tuck the chin down to lengthen the neck and press the shoulders to the mat.
Raise both legs, pointing toes with a slight turn-out (like a mini plie) to the roof
Keeping legs pressed together, take them to the 10 o'clock position.
Centre, then direct legs to the 2 o'clock position.
Repeat x 10 each direction
Double Leg Extension
Again, press spine into the mat firmly.
Curl the shoulders up away from the mat and lift the knees over the hips.
Inhale to extend the arms and legs as straight as you can.
Exhale to return knees over hips and arms reaching for toes.
Repeat x 10 - 15
Single Leg Teaser
Lie on your back, knees bent with heels aligned with hips. Raise one leg with thighs parallel.
Inhale to prepare and reach the arms up.
Exhale to curl the shoulders up away from the mat and reach for the toes of the raised leg.
Inhale to curl back down (don't drop!)
Repeat 8 on each side
Plie with Elbow to Knee
Get into a wide plie position, making sure your knees are tracking toward your 2nd toe.
Knees aligned over the ankles.
Maintaining your lower body in perfect stillness, take fingertips to ears.
Lower the elbow towards the knee then return to centre before reaching to other side.
Repeat 10 on each side
Single Leg Extension
Stand with feet hip distance apart.
Draw the belly button towards the spine and contract the shoulders to open the chest.
Maintaining the hips at the same level (don't hitch up on one side!), extend one leg back as you reach forward.
Hold for a count of 3.
Return to standing on one leg.
Repeat 10 times each side
Beware: Don't twist at the hips! Think about maintaining the hip bones in the same direction at all times
Tabletop Elbow To Knee
On your hands and knees, with wrists directly under shoulders and knees under hips.
Draw belly button to spine and avoid arching the back or rounding up.
Lengthen the back of the neck and direct the crown of the head forward.
Extend alternate arm and leg to make a long straight line.
Hold for 2 seconds then bring elbow to knee in the centre.
Repeat 10 times each side